1993 Suburban Fuel problem maybe

1993 C1500 350 TBI The problem started with hesitation and stumbling on take off and heavy loads. The harder you push the gas the worse it runs. Total loss of power. Now it barely runs and then will run but not great. Sometimes idles fine and then dies. Sometimes idles with regular surges with a sound like a muffled duck quacking (what did he say?). It can be driven with a lot gas pedal manipulating. If it dies at idle the pump goes through it's standard running time as if you just turned it on. I know this system doesn't stay pressurized but would think it should have some pressure at shut off. The fuel pump is only a couple of years old and is barely audible. Pressure is supposed to be between 9&13 and is 11. Fuel filter just changed. It was time for a tune up so new cap, rotor, wires & plugs installed. I did the "unplug the fuel pump relay" test and the engine dies indicating a faulty oil pressure switch. I'm going to change that tomorrow. I would have thought a faulty oil pressure switch would kill the engine shortly after start up. I'm wondering if any one has experienced it wreaking havoc with fuel delivery.

My 91 Suburban has the same TBI w/350 motor. My pressure switch is located under the distributor. If you location is the same, you'll have to remove the distributor to gain access.

Like I told another member with somewhat the same problem, check your injectors. When u get below 1/4 tank of gas air gets in the lines and can clog up and dry out the injectors. U may be able to purchase injector cleaner and get away with that helping fix ur probelm or u may need to clean them urself or have it done professionally. This is just from my own experience and about 20 fuel filters.

Timing chain, also. Just a possibility, similar symptoms when bad.

It's good to know that folks are still interested. I've already cleaned the injectors and overhauled the throttle body. Regarding the timing chain, wouldn't the timing be off if the timing chain was worn? I checked the timing a while ago, checked out ok.

Now on to my latest saga. Pulled the fuel filter and found debri in it. Then I set up a filtration system recyling the filtered fuel back to the fuel tank. Reconnected the fuel system. Attempted to drive the truck, no luck. Pulled the fuel filter again, again debri in the filter.

Now I have pulled the fuel tank and have found rust spots. I have found a new tank for $95, 31 gallons. Can I get a better price anywhere else?

I'll know in about five days if this fixes my problem.

Hey dude, me again I found you a 42 gal. for bout 189-200 depending on weither or not u want new straps. Thats the best Ive found so far but ill keep on it for ya.

Alright looks Like the best I could get ya is a 42 gal. for $119.00 brand new comes with 3 year warranty. Heres the IP
http://www.1aauto.com/1A/GasTanks/ChevyTruck/Suburban/GM43A/8824

Thanks for your help. I really hope this is the root cause. Good thing I plan on keeping this truck for a while. By the way, I don't see very many in the junk yards!!!:0

I have the same problem. '91 5.7 4x

Swapped out; ign mod, pick up coil, cap/rot, egr valve, rebuilt tbi and replaced injectors with pick and pull donor, Plenty of spark, reset timing ala bypass mode. Plugs are a little oily from all the problem chasing but they are new and now need replacing. With a vac gauge connected to pressure line at tbi I have 9 lbs.pres. at on and not cranking. I am going to;
--check fuel pressure via valve at back of manifold during crank and operating mode
--MAP gave bad second read (ground and sending wire) on good tester.

I will provide results.....


No luck so far. TPS changed out due to bad read during throttle increase (thought I had it) New TPS - Same problem.

Will check fuel pressure and report back, I'm leaning towards the pump. Any thoughts would be great

Alright now i'm getting mad. Swapped out temp sensor and still no luck. Now onto the pressure test.

Anyone know the answer here...