1992 lumina Euro 3.1
My car runs decent at up to 3/4 throttle, if you smash the gas pedal down, it loses power and slows down, let it back to 3/4 throttle and it picks up speed again. if I keep it at 3/4 throttle in second gear it will continue to pull up to high rpms, so I am kinda ruling out the fuel pump, or filter. I have 38 PSI fuel pressure. I cleaned the IAC valve which cured my idle issue, and did the re-learn procedure, it will idle fine, no probs when stopping. ANYONE have a guess or similar experience? I know these cars have injector probs, but it wouldnt make sense that only at full throttle it dies out. I am going to do the ohms test on the injectors later on to rule those out, but just looking for some advice in advance! thanks

1992 lumina Euro 3.1
My car runs decent at up to 3/4 throttle, if you smash the gas pedal down, it loses power and slows down, let it back to 3/4 throttle and it picks up speed again. if I keep it at 3/4 throttle in second gear it will continue to pull up to high rpms, so I am kinda ruling out the fuel pump, or filter. I have 38 PSI fuel pressure. I cleaned the IAC valve which cured my idle issue, and did the re-learn procedure, it will idle fine, no probs when stopping. ANYONE have a guess or similar experience? I know these cars have injector probs, but it wouldnt make sense that only at full throttle it dies out. I am going to do the ohms test on the injectors later on to rule those out, but just looking for some advice in advance! thanks

Want to add, I have a brand new battery, NO SES lights, NO stored codes, NO bad vacuum lines, I have researched as much as possible, but I need help on this one, the car also has new plug wires.

Leave the fuel pressure gauge on it and tape it to the windshield if you have enough length, watch it when you go WOT.

Might wanna do a vacuum test to rule out a cat restriction, etc.

Might wanna do a vacuum test to rule out a cat restriction, etc.

Well I know its not the cat, because I had to fix an exhaust leak, and when it was out I put a vacuum cleaner hose on one end and turned on the vacuum and it had no restriction whatsoever.

I just remembered something else, I had a 1998 chevy pick up that died on me, replaced fuel pump, filter relay, and it happened again! I ended up running a higher guage wire to the pump and it never had another problem, I might try that too, I will update this post if that cures it! GM likes to run tiny wires to the fuel pumps. I actually did that on my 97 grand prix as preventative maintenance, and that car has almost 220k miles on it! That or the fuel injectors is my guess, but keep the posts coming! thanks!

Your cat test won't work, the element in the cat can move with exhaust pressure, partially blocking the outlet. A pressure test on the o2 port at 1500 rpms should not be over 1.5 psi.

Or a vacuum gauge connected to manifold vacuum should hold steady when running at high RPM, slow drop indicates restriction.

Or a vacuum gauge connected to manifold vacuum should hold steady when running at high RPM, slow drop indicates restriction.

ok did the test, NOT the cat, and actually it looked pretty new (car has 185K ,iles on it)

I ran a new wire to the fuel pump, it didn't seem to change the effect.

now if I shift into 1st gear from a stop, slowly take off and at about 10 mph nail it, it falls on its face like you lost all power, bring it back to 3/4 and it keeps going, this is getting annoying! I bought the car from an auction, and it looks like someone else has already tried numerous things to try and fix it. It has a new EGR also. I guess I will just check the injector values so I can rule those out.

Get an ohm meter reading on the throttle position sensor , then sweep the throttle open and closed slowly and look for a dropout in reading.

Get an ohm meter reading on the throttle position sensor , then sweep the throttle open and closed slowly and look for a dropout in reading.

Checked all injectors, had 12.7 ohms across the board, and replaced the fuel filter for the heck of it. Cleaned the EGR ports while intake plenum was off, egr valve is NEW. They were not horrible, but a little carboned up. I will check the TPS next, but I am running out of things to check!

The trans will downshift at full throttle, so I cant see it being the TPS either, but its worth a check!

Checked all injectors, had 12.7 ohms across the board, and replaced the fuel filter for the heck of it. Cleaned the EGR ports while intake plenum was off, egr valve is NEW. They were not horrible, but a little carboned up. I will check the TPS next, but I am running out of things to check!

The trans will downshift at full throttle, so I cant see it being the TPS either, but its worth a check!

TPS ohms are in check too, This must be an odd thing or something, I was hoping this was one of those things that just happens and there was an easy fix, guess no!

1992 lumina Euro 3.1
My car runs decent at up to 3/4 throttle, if you smash the gas pedal down, it loses power and slows down, let it back to 3/4 throttle and it picks up speed again. if I keep it at 3/4 throttle in second gear it will continue to pull up to high rpms, so I am kinda ruling out the fuel pump, or filter. I have 38 PSI fuel pressure. I cleaned the IAC valve which cured my idle issue, and did the re-learn procedure, it will idle fine, no probs when stopping. ANYONE have a guess or similar experience? I know these cars have injector probs, but it wouldnt make sense that only at full throttle it dies out. I am going to do the ohms test on the injectors later on to rule those out, but just looking for some advice in advance! thanks

It may have something to do with built in over rev protections or a throttle governor. Or you may not have enough fuel flow to make it work at high engine speeds.

It may have something to do with built in over rev protections or a throttle governor. Or you may not have enough fuel flow to make it work at high engine speeds.

Nothing to do with an over rev limiter when its in "d" and you are doing 40 and hit full throttle and it slows down.

and not fuel related either

I got nuthin.....

is it possible the transmission is acting up, you say its fine in second gear... but in third it loses power. and since you have the Euro im sure you have the 3 speed no overdrive TH125c like i do.

I'm having the same problem with my '98 Lumina with 3.1L. The full throttle issue does not always happen significantly, but there is a power loss at times. If the TPS does have a flat spot, will the computer show codes? Mine has none.

Thanks

the computer will usually not show codes for a low spot on the tps. if you know it has a bad spot, do your self a favor and replace it, its not that expensive, a dn will probably fix your issue

1992 lumina Euro 3.1
My car runs decent at up to 3/4 throttle, if you smash the gas pedal down, it loses power and slows down, let it back to 3/4 throttle and it picks up speed again. if I keep it at 3/4 throttle in second gear it will continue to pull up to high rpms, so I am kinda ruling out the fuel pump, or filter. I have 38 PSI fuel pressure. I cleaned the IAC valve which cured my idle issue, and did the re-learn procedure, it will idle fine, no probs when stopping. ANYONE have a guess or similar experience? I know these cars have injector probs, but it wouldnt make sense that only at full throttle it dies out. I am going to do the ohms test on the injectors later on to rule those out, but just looking for some advice in advance! thanks

Hi, did you find what was causing this problem?

I am having the same problem with 1998 Lumina 3.1. I replaced cat converter, changed fuel filter but still have the same problem.


The problem occurs only after the car is warmed up. In the morning, the car runs fine for approximately 10-15 minutes but then develops the same problem - it just does not have any power if I press the gas pedal beyond the halfway.


If I keep the car in the first or second gear while pressing the gas halfway, the car would slowly accelerate to high RPM so the fuel pump seems to be fine.

The car does not show any codes.

My problem is not that bad. It is intermittent. i.e., when I hit the throttle about 3/4, I start to get misses that show on the tach. This does not always occur. I think it may be the Throttle Position Sensor, but need specs on that to check. I checked output voltage from the TPS, and it is consistent to what I think was about 4.5 volts. Otherwise, I am lost, as the car does not show codes, and otherwise drives flawlessly. I'd check / replace your TPS, then let me know what you find.

I didn't see it mentioned, but what about a weak coil, plug or wire. These can act fine until you mash the throttle. This increases pressure in the cylinder, now the coil has to increase spark power to overcome this pressure. This is when mis-fires happen. Also, you say it isn't fuel related, but my book shows a min. of 41lbs of fuel pressure, 47psi highest with KOEO 3 lbs from minimum may not sound bad, but Thats LOW!! On average, an 8% drop in fuel pressure causes a 58% drop in fuel FLOW. I'd start checking for at least 15" of vacuum at the pressure regulator. Next would be to test pressure AND flow..

I didn't see it mentioned, but what about a weak coil, plug or wire. These can act fine until you mash the throttle. This increases pressure in the cylinder, now the coil has to increase spark power to overcome this pressure. This is when mis-fires happen. Also, you say it isn't fuel related, but my book shows a min. of 41lbs of fuel pressure, 47psi highest with KOEO 3 lbs from minimum may not sound bad, but Thats LOW!! On average, an 8% drop in fuel pressure causes a 58% drop in fuel FLOW. I'd start checking for at least 15" of vacuum at the pressure regulator. Next would be to test pressure AND flow..

I also thought that this could be caused by either fuel or electrical problem. However, as it was recommended on this forum, I tried to accelerate in second gear to see if there are any problems with the engine on high RPM. The car easily accelerate to 65 mph if the gas pedal is pressed less than halfway. So I guess the pump and ignition should work fine.

But I went ahead and changed spark plugs, spark plug wires and oxigen sensors anyway - although the engine seems to be more powerful now, this replacement did not solve the hesitation problem occuring when engine is hot and gas pedal is pressed more than halfway.

My problem is not that bad. It is intermittent. i.e., when I hit the throttle about 3/4, I start to get misses that show on the tach. This does not always occur. I think it may be the Throttle Position Sensor, but need specs on that to check. I checked output voltage from the TPS, and it is consistent to what I think was about 4.5 volts. Otherwise, I am lost, as the car does not show codes, and otherwise drives flawlessly. I'd check / replace your TPS, then let me know what you find.

Hi, GreySVO, did you have any luck with replacing Throttle Position Sensor?

Currently I am thinking about replacing the Throttle Position Sensor and may be looking at Transmission Control Solenoid. :confused:

The car easily accelerate to 65 mph if the gas pedal is pressed less than halfway. So I guess the pump and ignition should work fine.


There is less requirement for fuel in a lower gear, because the engine isn't straining as hard..

Now I am frustrated. I was driving home, playing with the '98 with 3.1L, and floored it... the engine missed and made no additional power. Otherwise, this car drives flawlessly! What can be the problem? I've checked the TPS, changed fuel filter, plugs, wires, and air filter. Any other ideas? Can a coil do this? Any way to cehck the coil? Other checks to perform? Oh yah, and no codes... HELP!

Hi, GreySVO, did you have any luck with replacing Throttle Position Sensor?

Currently I am thinking about replacing the Throttle Position Sensor and may be looking at Transmission Control Solenoid. :confused:

Finally I replaced the TPS but this did not solve the problem. :banghead: :wtf:

I've not had any luck yet, with any parts replacement, or help!

Anyway, I bought a new EGO Sensor, and will install that this weekend. The car has 136,000 miles on it, so maybe it is worn, as I am starting to smell more fuel in the exhaust... which indicates to me I am not getting good combustion. Idle is good, so I am guessing it is not too high fuel pressure.

The anomoly is also like this... when I floor it, the engine misses as if its hitting a rev limiter... will keep the speed, but will not speed up.

Again, any help from anyone else will be very much appreciated.

Tried a new pump yet?

Tried a new pump yet?

Nope. But accordingly to the recomendation on this forum, I tried to drive on a highway in the second gear and the car accelerates slowly to ~70 mph (with the gas pedal pressed halfway) and runs stable at that speed. This seems to indicate that pump should work fine, do not it? New pump is quite pricey and I do not want to change it until there is a clear indication that the pump should be replaced.

There is less requirement for fuel in a lower gear, because the engine isn't straining as hard.. I agree that the load on the engine is not that great but I would think that the load on the PUMP is quite significant if the engine is continously running at 4000 RPM. Is it correct?

I can rev my engine to 4000 in neutral, and then in each gear with a flow and pressure guage. There's hardly any flow at all in neutral, but a considerable amount when in gear travelling. Besides, you mentioned you only have 38 psi, which is well short of the 41-47 psi needed....

EDIT: The only way to ACCURATELY test a pump is with a flow and pressure guage, not by acceleration..

You describe the same issue I had with my 96 3.1 2 years ago when it had about 125,000 miles). It would act as if the rev limiter would kick in. I want to add that mine would only occur under 2 circumstances that you didn't list. The ambient temp had to be above 80 F and the engine compartment had to be at operating temp(3-5 miles to warm up). The revs would continue to come down as the engine compartment got hotter, like when slowing down for a small town, or finding myself behind a slow truck/tractor. If I feathered the foot feed lightly, I could get the car back up to speed and it would seem OK until I tried to accelerate hard.
Anyway, I was able to eliminate the fuel system as the issue. Also eliminated the exhaust/cat as the issue. I had no codes. I checked/swapped all the coils & ignition module. No improvement. I replaced the plugs/wires and found several plugs to be bad (platinum tips gone). FYI, I checked the plug condition regularly as the miles(on the plugs) crept past 100,000, but I only looked at the easy access front plugs. I won't make that mistake again. Anyway, the new plugs/wires helped the rev limiting problem substantially, confirming ignition as the problem. However, I could still get it to act up on 90+ F days when towing my small fishing boat, and accelerating fast. I gave up on trying to troubleshoot any furthter beacause it was so rare that I would drive in that high temp/High load condition.
Chapter 2......
About 6 months ago, the alternator finally failed with 185,000 miles on it. I knew from previous testing that the old alternator charged at a low 12.8 -12.9 volts since day 1. Seemed low to me but the car never complained.
After installing the new alterntor, I observed that it charged at 13.4 volts, but thought nothing of it at the time.

With the hot weather here recently (90+ in fargo, nd), I was towing the boat and wanted to verify that the high throttle rev issue still existed. IT PERFORMED PERFECT AT WOT!!
The theory is that the coils now have more primary voltage to work with, therefore more potential secondary voltage is available at the plug gap. If this theory is valid, I would assume the same result if you closed the spark plug gap slightly.....say from .060" to .055".

Hope this provides some insight/ideas. PLEASE LET ME KNOW if you or anyone else can reproduce these results. I would appreciate some confirmation that low voltage was my issue.

You need a fuel pressure regulator. Under load, at WOT, the FPR isn't closing, and you're starving for fuel. Since it happens in all gears, it's not tranny related. An FPR can work fine at idle and part throttle, but not close completely enough at WOT due to a pinhole in the diaphram to keep fuel at the injectors. Check the vacuum supply line at the FPR, if it has fuel in it, you found your issue for sure.

Check the fuel pressure under load. Sounds like a clogged fuel filter.

Finally, I fixed it. This problem was caused by a faulty crankshaft position sensor. The dealer said that the faulty crankshaft position sensor also fried the computer (ECM) and thats why the computer did not show any codes.

Both ECM and crankshaft position sensor were replaced at a quite hefty price but the car works well now. Taking into account all other replacements (fuel filter, spark plugs, spark plug wires, trottle position sensor, catalytic converter, and both oxygen sensors) it took more than $1000 to fix this problem. :disappoin

sounds like hod wash to me. Your car ran? if the cps wasn't functioning, there would be no way for the pcm to know what position of the crank is in, and wont be able to send spark or fuel injector pulses at the right time. Therefor your car would not, and should not have ran at all.

your dealer is smoking crack. There is no way a bad crank sensor can fry an ECM. I'd avoid taking your car back there, as it sounds like your crank sensor was bad and they hit you for an ECM too.

Yep. Either that, or they fried the ECM testing out the CPS circuit..

Folks, thanks for your comments. I would not go to these guys anymore. :shakehead