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I lubed all o-rings upon assembly with plain old motor oil. The O-rings on the back of the plennum where the nut kit's collars go got it, the O-rings in the fuel lines going to the injector get it...however, there were no o-rings on the fuel lines going into the nut kit collars, nor in any other fuel line I have removed and replaced. Including the fuel filter. There are flared ends and as long as they are *clean*, when you snug up the collars, they should seal fuel tight, no problems. But petroleum jelly does make a good sfety blanket and keeps the ends from getting stuck when they have to get removed later on. Good show! I should have taken photos when I did mine, but the interior of my plenum was so FILTHY, there was no way in hell I was going to operate my rather expensive camera with funky hands. It took the better part of a week for my hands to completely clean up after this job. Good work!

Nice post like the pics and descriptions.I agree with you if you got a manual or instructions anything is possible as long as you follow them>wolfox my hands are still filthy from rebuilding 5.7 i went to class thursday night and im like its not coming off no matter how hard i try.

Yeah, the blending of motor oil from the PCV system, raw, untreated exhaust pumped in through the EGR before the catalyst, and years of micro-fine dust that an air filter will never catch makes for a greasy amalgam that can only be described as really disgusting, sticky Xerox toner. :D :lol:

Excellent Post. Just reading through you comments makes it all the easier to do the job. I've replaced 3 CPI and nut kits on my 3 Blazes already. The first time was like you. By the book, and it took so long going back and forth. If I had this. I would of been just screaming along and done in half the time. Great Job!!!!!!!!!!!!!!

Oh, oh! I ran into this problem when taking the old poppets out:

I had three of the clips breaks off, locking the poppet into place in the lower plenum's intake ports. Using a thin, and I mean *thin* pair of needle nose pliers, reach into the port along the side where the "ear" for the retainer broke off and grasp what's left. It takes just a firm tug to break the rest of the ear and the retaining tab off on that side. Then using the side of pliers' nose as a brace, I pushed on the remaining, intact tab and was able to wiggle the poppet out of the socket eassily. When putting the new ones in, seat the new injector assembly first after installing the fuel lines. Install the fuel lines first so you can work out the routing of the poppets on the driver's side with a bit of ease. Contrary to belief however, it is not important which order they go in, as the system is batch fired. However, the varying length of the injector pigtail tubing will define where the injector goes. Remember, no sharp bends or kinks and you will be alright. One of my injector lines indeed have to go over the fuel lines, as this was the only way it would go without any rubbing which would lead to pre-mature failure.

I figured what the heck, while I was in there and did what you did, replaced cap and rotor and also took off my EGR to clean it up thoroughly and put it back in. It was sticking due to carbon build up brought on by my regulator leaking. It also fouled out the #4 plug. Though she started up and idles much better, it still loped because of that. A quick replacement with a fresh plug took care of all of it. It's a very satisfying job when it comes together and works, eh? Rock on!

93LT Excellent, Excellent picture post, you may have just helped out a thousand 4.3 owners, that said, This thread should be stickied...

Thanks everyone, I just noticed a typo. It was supposed to say "without a manual". I don't have one. Would like to get a factory service manual some time though. It took about an hour for me to tear it down, making note of what bolt went where (not all upper plenum bolts and studs were the same length). When the parts arrived the next day, it took about an hour and a half to reassemble. To give those still in doubt how simple this repair actually is, there was no cussing or throwing of tools involved.

I had read enough on this board and another to get an idea of what to look for and was aware of the plastic tabs breaking on the poppet valves, fortunately for me, mine didn't break. While this was a pretty simple repair, I'm a seeing is believing kind of guy and thought posting some picutres might help some others that might not be so sure about the repair, now maybe they can get on to better running and better gas mileage.

Where did you get the "NUT"kit witht he fuel lines? I am replacing my CPI and everything to go with it but Checker doesnt carry this so called NUT KIT. Do you have a GMpart number I could reference?

Nice, this is will help alot of people. By far the best CPI/NutKit replacement pics that I've seen.

The AC/Delco part numbers are:

Nut Kit: 17112705
Fuel Injector: 17113673

Thank you so much! This is goin very smoothly so far with the help of all these forums!

awsome pics. i did my first cpi replacement in august. i had a busted fuel regulator and a hole in the nut kit. i'll throw up a pic of it later. i had a manual but i only needed it for the tightening sequence for the plenum bolts. the biggest problem i ran into was that the torx bolt holding the nut kit was stripped. i had to buy $100 worth of stud removers to get it out. i worked on it for a hole weekend but got it done. i also changed the oil and performed a complete tune-up. the truck runs great know.

can someone tell me the torqueing specs and pattern for the bolts that hold down the lower intake manifold? i took it all off cause my gasket was blown!

You have a total of 12 bolts that hold down the lower manifold. 6 on the left and 6 on the right. Tighten all bolts hand tight first. The following is the tightening squence you need to use. Left side starting with front bolt. Tighten order is 12, 5, 4, 2, 7, 10, Right side starting with the front bolt. 11, 6, 1, 3, 8, 9.
Start with bolt number one and work your way to bolt number 12. You need to tork them down to 35 ft. pounds (48Nm). Sorry didn't have any diagrams handy.

AWESOME! That helps so much I dont have the extra money to spend on a manual. The upper intake bolts is 18ft lbs I believe right? Not much real order needed for tightening those though right?

The upper are 18 inch pounds, not foot pounds. the order should be in a cress cross pattern.

Nice post and some great photos.

Your engine is really clean. You upper plenum is really quite dry and you can tell you engine doesn't have a lot of blowby seeing it has no oil saturation.

You should be good to go for years now. You got it before it caused you any damage and I commend you on your effort. That Felprogasket looks a lot better than the AC delco I used.

Did you clean the EGR port?

Nice post and some great photos.

Your engine is really clean. You upper plenum is really quite dry and you can tell you engine doesn't have a lot of blowby seeing it has no oil saturation.

You should be good to go for years now. You got it before it caused you any damage and I commend you on your effort. That Felprogasket looks a lot better than the AC delco I used.

Did you clean the EGR port?

I didn't do anything to the EGR port. I do believe someone already had as the EGR Valve already had a screened gasket installed (which I replaced with another screened gasket).

I just bought this Blazer last week, as is, from a used car lot that had bought from a CarMax in KC, KS in April of 2004. Said they drove it 100 miles home, when they came back to it the battery was dead (has some blasted alarm system on it that probably ran it down, I need to remove this), it sat awhile longer before they put a new battery in it and it would start. So it has esentially sat for over a year. I could tell, the previous had taken good care of the care mechanically and cosmteically. It ended up being a one owner from a guy that worked at the GM Fairfax plant in KC, he had bought it as a Demo (all paper work was with the vehicle saying so) with 3967 mile on it. I got it with just over 110K on it. I did no cleaning tot he engine compartment prior to taking my photos.

Very happy with my Blazer and getting ready to get a stereo system for it. You win some and you lose some, but I'm very pleased with my purchase, even though my father-in-law couldn't understand me buying a car as-is and having to tear the engine apart to replace what is photographed in this thread to fix it.

Looks great, what I meant by the EGR port is the port in the upper plenum where that copper ring now is.

Looks great, what I meant by the EGR port is the port in the upper plenum where that copper ring now is.


It was a clean as the port by the EGR valve. The upper plenum was pretty much a mirror image of the lower plenum as far as how dirty/clean it was.

you are lucky, that engine is spotless inside. Far better shape than mine.

Just wanted to mention that after fixing the fuel leak, my gas mileage increased over 6 MPG. Routine driving I had just under 17 MPG ( I say "routine", actually I gave the motor quite a bit of grief to see how she would hold up after the injector/nut kit change, that would not be routine).

How far open should the fuel adjustment knob on the inlet line to the plenum be? I just opened mine like a half turn from closed and it seems to be running ok but I dont know for sure...

How far open should the fuel adjustment knob on the inlet line to the plenum be? I just opened mine like a half turn from closed and it seems to be running ok but I dont know for sure...


Fuel adjustment knob? Are you talking about the Pressure valve on the inlet line right behind the plenum? If so, that is a cap, like on a valve stem, keep it closed.

Oh yeah thats what Im talking aboooot so just keep it closed. thanks!

OH GOD! I changed gaskets, CPI, Fuel lines(NUT KIT), hoses and cleaned EGR and port and when I run it then shut it off go back and start it after like an hour it starts real rough and chugs for about 2-5 secs then is fine. Now it did this a week ago and overheated and that was the whole reason I replaced all those parts cause Meineke told me thats what was wrong. Do I have a blown or small hole in my head gasket now? Im freakin out here

Ok Anyone interested in 95 Teal Green Blazer with 172k and probable head gasket problem. New CPI, Fuel Lines, hoses, brakes, front suspension and barely any rust from WI? 2grand just take it!

Ok Anyone interested in 95 Teal Green Blazer with 172k and probable head gasket problem. New CPI, Fuel Lines, hoses, brakes, front suspension and barely any rust from WI? 2grand just take it!

Those parts you replaced cannot cause a head gasket to blow nor will it cause it to overheat.

Stop listening to the brake monkeys at Meineke and go to a proper shop to get it inspected.

well what else could it be where I am just losing coolant after new radiator, hoses, gaskets? It starts rough as if it was compressing liquid in the chamber instead of gases. I am going to check a plug or two tonight but I dont have money to keep taking it to shops to diagnos ya know. This thing has already drained my account of flow.

Ok heres whats happening now, I just went out for lunch and started it and it started rough then smoothed out then as I sat at McDs it started to idle rougher and rougher so I floored it in nuetral and it smoothed out. Then as I sat there longer it started to get hot like above half way on the guage. So I started back to work and it cooled back down. Im sooo lost

How about you start looking into your cooling system to see if it is topped up instead of driving around with it running this way.

well what else could it be where I am just losing coolant after new radiator, hoses, gaskets? It starts rough as if it was compressing liquid in the chamber instead of gases. I am going to check a plug or two tonight but I dont have money to keep taking it to shops to diagnos ya know. This thing has already drained my account of flow.

It isn't that, your rad cap could be defective and not holdig pressure, but the CPI injector will not cause an engine to ovreheat.

Well I have checked it cold every morning since i finished the job and its low before I ever even run it if thats what you mean? I was told to do my Fuel Pressure Regulator so I called all over the place and no one seems to know what Im talking about. So where the heck can I order one from online cause I am having no luck at local shops!!!

Well I have checked it cold every morning since i finished the job and its low before I ever even run it if thats what you mean? I was told to do my Fuel Pressure Regulator so I called all over the place and no one seems to know what Im talking about. So where the heck can I order one from online cause I am having no luck at local shops!!!

Ok, relax a bit, you are coming across quite frantic.

1.) What coolant are you topping the rad up with in the morning? Are you topping it off when it is low? Are you topping up the rad or the overflow tank?

2.) Replace the rad cap with something that is not AC delco, get the appropriate Stant Branded cap from your local Autozone.

3.) The new CPI injector has the new regulator on it. It is brand new. Don't listen to your friend anymore, he doesn't know what is going on and is only confusing you.

You just had your rad replaced? How long ago?

ok this last week I replaced the CPI, radiator, hoses, gaskets and cleaned the EGR. I have a Prestone radiator cap and I use the orange dex-cool. Could it still be the ween hole and seal in the water pump?

ok this last week I replaced the CPI, radiator, hoses, gaskets and cleaned the EGR. I have a Prestone radiator cap and I use the orange dex-cool. Could it still be the ween hole and seal in the water pump?

No, you would smell it if you had a leak.

Are you mixing the dexcool and water 50/50?

also, remember when you replace cooling components you are going to have to purge the air out of your cooling system.

T do this drive your engine up on ramps and while cold remove the rad cap and get inside your truck and turn the temp dial all the way to hot and set the controls to heat.

Fill your rad to the top and then startup your engine, have the engine set to run at about 2000rpms and allow the engine to come up to temperature.

Watch as the thermostat opens and the coolant in the rad drops considerably. Keep on topping up the coolant until it doesn't drop anymore. It might burp a couple of time and the rad level will drop as the air is burped into the rad which will allow coolant to replace it.

when after 10 minutes the level does not drop, attach the rad cap on again and return your engine back to idle.

Fill the overflow tank to 1/2 inch below the overflow line connection you will see when you look into the overflow tank.

Also, did they flush your overflow bottle out?

Did you change your oil after the CPI replacement?

Well Im mixin 50/50 but the purgeing I have not done. I dont have access to ramps though so I will have to figure something out. I also did not flush out my overfill tank. I did however change my oil after I finished the CPI. I appreciate all your help so far.

Get one of those syphon hoses with the pump on the end and pump out the overfill resevoir and flush it and pump it out about 5 times to get rid of all the grime and crud that could be blovking the coolant passage that keeps the rad topped up when the level drops.

OH GOD! I changed gaskets, CPI, Fuel lines(NUT KIT), hoses and cleaned EGR and port and when I run it then shut it off go back and start it after like an hour it starts real rough and chugs for about 2-5 secs then is fine. Now it did this a week ago and overheated and that was the whole reason I replaced all those parts cause Meineke told me thats what was wrong. Do I have a blown or small hole in my head gasket now? Im freakin out here

If you had a head gasket leak, you should see water being steamed out of your exhaust pipe, more so than just engine warm up steam on a cold day. Also, you would notice the antifreeze level going down in the radiator/overflow tank, along with an antifreeze smell out the exhaust.

A plugged converter can cause over heating. Not saying that is your problem, just pointing that possibility out.

One other possibility with a jerky idle would be vacuum leaks, mainly the vacuum line off the back of the plenum, which goes to a "Y", then to a 4 way valve. From this valve it run to the main canister, transmission, cruise control and your ventilation controls (or at least it does on '94 and prior models). This same vacuum leak can cause your tranny to have spastic fits with the lock up tork converter, generally most noticeable when you first reach your top speed and level out under normal acceleration.

Another possibility for poor idling performance is bad plug wires. Yes, plug wires can give a poor idle yet run fine under acceleration.

ok this last week I replaced the CPI, radiator, hoses, gaskets and cleaned the EGR. I have a Prestone radiator cap and I use the orange dex-cool. Could it still be the ween hole and seal in the water pump?


What about a new thermostat?

I am not having a overheating problem like I thought sorry my thermo must have been stuck cause it worked fine later but still have the rough startup til I rev it. I will try to purge my system and clean the overflow tank and add coolant if needed. All these ideas are starting to get off on different tangents and I can only do so much more. I also do see alot of steam at start up even when it was 52 this afternoon so I will smell the exhaust and watch the levels tomorrow and see what happens.

The photos in this seem to help people comprehend the task at hand, how out a sticky?

As you can see by this first photo I was not as fortunate, and did not catch it early. The whole left side is fuel washed because of my leaky fuel pressure regulator. It also looks like injectors 1 and 3 are starting to leak a little too. Though this photo shows that my nut kit is not leaking (yet) I chose to replace it anyway.

http://i15.photobucket.com/albums/a358/Cailen/UpperManifold.jpg

My EGR was about 30% clogged and I'm fairly certain I'll need to be replacing my cat soon. It was so bad I decided to take off the complete manifold and clean up what I could. Below is a picture of the lifter valleys, as well as a picture of an exhaust port that was almost entirely clogged with rock hard carbon.

http://i15.photobucket.com/albums/a358/Cailen/LowerManifold.jpg

http://i15.photobucket.com/albums/a358/Cailen/LowerManifold2.jpg

And of course, just for good measure:

http://i15.photobucket.com/albums/a358/Cailen/goodmeansure.jpg

I always wondered what the balance shaft looked like in the 4.3 engine. That was first added in 1992, and only the vortec engine received it initially. I believe by 1993, all 4.3 engine received the balance shaft.

I had a 1992 Full Size Chevy Short Bed Sport (new) with the TBI version, it was one rough idling engine.

I believe those ports are for your EGR valve gas circulation and not your exhaust and that would explain the carbon buildup from a rich running engine. I wouldn't cause too much of a problem but it will be limiting the EGR gas going into the cylinders. No biggie but make sure you clean it out good. Been noticing any pinging lately?

Also, I notice that you have the wrong plug wires installed. Your should not be using 90 degree boots but straight boots on the cap end.

Overall, looks like you have had a leak for a while seeing the carbon buildup in the upper plenum.

How have was it to remove the lower intake?

Ahhh yeah that makes sense on the EGR. I chipped it all out / vacuumed it up good.

This was done a while ago.. and you're right, the previous owner had vertical plugs on it, not horizontal ones. I noticed that about when I had that lower plenum off too.

And if you look at the last picture... about 10 beers hard. LOL

Seriously though, it took me 2 hours from unplugging sensors to lifting off the lower manifold and I could do it in about 20-30 minutes now. Putting it back together was another story.

The first time I put it back together I bolted it all down and had one bolt that wouldn't go in; had to take it all back apart. I took a die to the stubborn bolt cleaned it up, and I grabbed a thread cleaner from a friend: bad idea. The thread cleaner snapped off in the bolt hole. I had to drill out the center of the cleaner and use my dremel with a grinder to get the rest out, and then install a new heli coil.

Then I got it all bolted down and went to connect the inlet and return lines but they wouldn't go, so I had to unbolt it, fix the threads up on those and do it all again.

Then I put it back together AGAIN and when I started it up coolant pissed EVERYWHERE: didn't know I wasn't supposed to use rtv on the gasket surface. You should have seen how much coolant was in my oil. Couldn't have been good for my crankcase.

Anyway, now it's running alright. I had significant noise before and it's much quieter now. Little bit of a lope now though.

The second time I put it back t

lol, sounds like you went through a lot, the beers probably didn't help though. hehehehe

Hope you used a torque wrench.

Mine smoothed up after good test drive, more so than the initial start up after completing the injector replacement.

Double check your vacuum lines for connections and cracks. If you grab your vacuum lines and your hand turns black, replace the vacuum line.

Mine smoothed up after good test drive, more so than the initial start up after completing the injector replacement.

Double check your vacuum lines for connections and cracks. If you grab your vacuum lines and your hand turns black, replace the vacuum line.

Good point.

Any update on this, I fund this thread really interesting.

Is your request addressed to me or Cailen? Or perhaps someone else?

I too find all that is involvedin this thread from other contributors rather interesting.

Blackmarocraig probably... I'm quite interested in his problem too.

Is your request addressed to me or Cailen? Or perhaps someone else?

I too find all that is involvedin this thread from other contributors rather interesting.

Both sets are awesome.

I didn't think I had anything more to add, but I found another possible contributor to that nasty carbon buildup. It's obvious after today that since I've owned my truck the tstat has been stuck open. My temperature has never moved from about 50 or 60 C. It now definitely reaches operating temperature, and you can tell when the tstat opens (temp goes down 10 or so degrees).

I'm going to fill up tomorrow morning... looking forward to posting any increases in gas mileage :) I've noticed a steady increase in mpg every tank since I replaced the CPI and did my lower gasket (to the tune of about 7%).

Sadly, I am still not blowing very hot air out of my vents still. I did an acid flush along with the tstat change and additionally I removed the hoses from my heater core and flushed a LOT of water through it. Any suggestions would be appreciative.

Make sure you burp the air out of the system and make sure the blending door is not jammed open.

I'm working on burping it already... Added some fluid to the rad when I started her up this morning. There's a LOT of air in the system. When I took her for a test drive last night after I finished the needle would drop 50 or 60 degrees and then pop back up.

Thanks for the suggestion on the blending door, I'll check that.

I'm working on burping it already... Added some fluid to the rad when I started her up this morning. There's a LOT of air in the system. When I took her for a test drive last night after I finished the needle would drop 50 or 60 degrees and then pop back up.

Thanks for the suggestion on the blending door, I'll check that.

Oh my, that is a lot of air still left.

Turn your heat to full hot and elevate the front of the truck on ramps and allow it to heat up until the stat opens and the level will drop as the air is displaced.

Yeh I poured probably half a litre in this morning when I was ready to roll to work. Could have poured more in but I didn't have any premix left.

Where did you get every part in the lower plenum? I seen new lines everywhere, and what the fuel injector sets in. Also, what did you use to seal the lower plenum to the upper? I am having probs just like the others, and this seems to be the ultimate fix.

Thanks for the thread it has helped me out very much but I do wish i would have looked it over first LOL might have had less problems

Hi, I am new to the Forum but have been lurking for about 2 years. Very good information here. I just purchased a 2000 GMC Jimmy SLT and am very pleased with the vehicle over all. After about 3 tanks of gas I realized that the mileage is pretty bad and just started noticing a hesitation at a constant speed ~60mph and then it recovers. Immediately thought the torque converter needed help. Took it to a tranny shop and everything checks out. I am wondering if this hesitation could be a fuel delivery problem. I found this thread and am now leaning that way. Is this a known problem 2000's as well or has something changed since the mid 90's models? Any and all input very much appreciated!

Thanks a lot for these pictures and your posts. I have a '95 Safari with 170K which has had driveability ttrouble for at least two years. I was aware of this CPI problem but just didn't hit my pain thereshold until mpg dropped to 13. An inspection via the tuning valve mounting hole indicated the only trouble was a leaking regulator but consulting several techs I know convinced me to spend the extra money and replace it all since I tend to drive a vehicle "forever." Yesterday I replaced everythihng inside the plenum. My GM dealers have "crazy" prices for OEM parts even with the discount of buying through a friend business. He and most of the techs advised that GP/Sorenson CPI unit gives good results. I installed the Sorenson CPI unit PN 800-1225N and a Motormite "nut kit" PN 55163. Saved me over $100 compared to deealer AC Delco. The performance of the van improved dramatically. After only about 15 miles the tail pipe was clean of the black soot coating. Idle and driveabilty is like new. The only unexpected thing I encountered I had not seen posted here was fuel pressure. The key on engine off KOEO pressure was 75 psi with the pump running then dropped to 67 with pump off. I wondered if the pressure regulator was defective allowing the 75 psi. A call to a tech assured me that was normal. I cycled the key several times to inspect for leaks and found none. Reassembled and upon starting was missing on 2 -3 cylinders. I thought perhaps, and hoped, it was just fuel starvation on some lines and after several revs and restarts it was running on all six. Took for test drive and realized I should have done this job two years and 50K miles ago. I probably paid for the parts a couple times in wasted gasoline. So, if you came to this forum SEEKING ANSWERS to your 92 - 95 4.3 ROUGH IDLE, POOR MILEAGE, HARD START problems you found the right place.

Very useful thread. I replaced everything in the plenum yesterday on my 95 Safari. Only trouble I had was uncertainty of fuel pressure. Key On Engine Off pressure with fuel pump running was 75 PSI. I needed to consult experienced tech to learn that was normal so long as the KOEO pressure was no higher than 66 or so witth fuel pump off.

more info about cpi injector in 93 blazer

I want to know where the vacuum line from the ball on the hood is supposed to be hooked on the motor on a 95 4x4 4.3l blazer?

I also have a 94 safari with the cpi. i replaced the cpi this weekend, i istalled the poppets in a row the way the come out of the unit. from left to right. is this correct? i put the center from the unit to the ceter cyl on that side. and the one that came out the front o the front cyl and so on. is this correct? thanks joe

Hi you guys. I realize this is an older thread, but I really could use your help. I also have been about to pull out my hair. Here's the story.

I bought this '95 blazer and and it developed fuel problems. The rpm's surge up and down when it idles, poor mileage, and it misses real bad. Diagnostics at the dealer showed a bad throttle positioning sensor, a bad transmission, and the o2 sensors were going nuts. It had flowmasters on it, but they have now been replaced with stock, along with the tranny rebuilt, and a new TPS.Same problem. A new digagnostics show nothing, but the dealer says its a fuel problem. It has a recent tune-up also. I have done everything else, and had come to the conclusion it might be a computer problem? NO? Sometimes its like the throttle would stick too. Nobody has a clue about this car and its nickle and diming me to death. You think this may be the problem?

I wanted to come back on here and tell you guys my "story" with this car, and what I've been through...and what "I" did to fix it.

No, I didn't burn the darn thing..lol
Original diagnostics codes were all repaired..stupid me. It even included a transmission. Made since to me since the throttle kept taking off and it shifted from OD/D. After 4 mechanics..neither helping at all, I read these forums. Trust me, everything yours is doing, mine was doing. It almost seened electronic. Here's what I did.

I removed the positive battery cable. I unhooked the ECM and cleaned all the plug-ins with Ether.I left it unhooked for about 2 hours while I....took out all the fuses, cleaned all of them and the connections. (Some were very dirty) I cleaned every connection I could find. I threw some Lucas fuel System Cleaner in for good measure, I replaced the TPS (again) and the Idle Control Valve. And then...I hooked up the battery and started the Engine.

I"ve had this car for almost a year now, and it has NEVER EVER ran like this or had so much power. It's like a totally different car.

I also found there were several recalls on this car. My brakes and the ABS are part of the recall. Link is below. I bought myself a manual, and the best part is...I finally fixed it myself. Wish I woulda done this 6 months ago. :banghead:

http://www.carsmart.com/content/own/service/index.cfm/action/RecallsView/seriesid/5162

Quick question for anyone who may be able to help. . .

I seem to be having the same problem as most of the people in this thread, with a couple of minor differences. I have a '94 Sonoma 4x4 4.3 Vortec, BTW.

1-The rough idle is not present until the truck warms up, then it idles and drives VERY poorly.

2-I have a bad exhaust "donut" gasket, and I haven't found time to change it yet, so there's a rather large exhaust leak.

3-The hesitation isn't consistent. When the truck's idle starts becoming more and more rough, the engine just loses all power and it will pop and rattle when I attempt to accelerate.

Any help is much appreciated, and I hope you all can help me resolve my problem quickly!

This is a very fine post and I wanted to add something of an update.
NAPA carries a OEM sourced NUT kit #CRB218477 =$72.49,
http://partimages2.genpt.com/partimages/545667.jpg
The lines without the Braket and screw #BK 7002370 +$44.99
http://partimages2.genpt.com/partimages/379305.jpg

pressure regulator #BK 7002368 $45.49http://partimages2.genpt.com/partimages/232760.jpg

I know this is an old thread But it has helped me beyond belief and deserved a BUMP! (i promise to try and not do it again...:( )

I'm another who was helped by this thread. My lower intake had fuel accumulated under the feed lines that was about .5 - .75" deep. For the longest time my blazer would idle up while braking from speed and I couldnt figure out what was causing it. There is a drain hole that goes into the #3 intake runner, every time I hit the brakes hard enough it would pour fuel into #3.:eek7:

There was a large crack (.10" huge) that I found on the return side while I was fixing this. What brought me here was that another leak finally got bad enought in the feed side to affect the idling and starting of the engine (fuel pressure) and a search on google led me to this thread.

Thanks to everyone who contributed to this thread!! My auto blazer will spin the tires going into 2nd again!!:):)


Can't wait to see the fuel economy gains.:biggrin: