first off the car is a 91 firebird with the 3.1 engine and auto tranny. here is my problem, the car will start and idle but as soon as you give it any throttle it dies.. i used my cheap code scanner to check codes, i showed nothing, i checked fuel pressure it was at 44 psi, checked tps it worked fine. so i had a buddy, bring in his snap on scan tool, it still couldn't find any codes. i am really getting frustated on trying to find out whats wrong with this car. has anyone else had a problem like this our have any ideas what might be wrong. thanks Marty
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Marty:
You mentioned that the car idles o.k....
Now, is that just from a cold start, or does it still idle o.k. once it's up to normal operating temp?
If it is idling o.k. after it has warmed up, and hence the EFI system has leaned the mixture back some at that point, and then after that it stalls when you open the throttle, I guess the first thing I'd be looking for is a vac leak. Have you measured manifold vacuum once it's warmed up?
Ken'94 Firebird Formula, Lt1, 6 speed, all stock -
it will idle for ever, we had it idling for 30 minute while we looked for things like vacuum leaks. no signs of any. i will double check the manifold vacuum later tonite.Comment
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when was the last time you did a tune up? have the plugs been replaced recently?87 GTA: it's winter time, all tore apart
ConElite: "Im 22, have had my TA since I was 21."
"I wont lie, I have a heavy foot, but at the same time I know when its the safest to ring out a gear or 2."
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Marty,
How'd you make out with this bird? Did you get a chance to measure the vacuum at the manifold? Sure sounds like something is throwing the mixture outside the desired range, which would be most likely to show up when you open up the throttle and the vac drops momentarily, producing the stall.'94 Firebird Formula, Lt1, 6 speed, all stockComment
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Did you try flashing codes by shorting the ALDL pins?
Did you verify the fuel pressure at anything other than idle? Does it hold 44psi as engine load increases?
I believe the 91 3.1L is a speed-density setup (no MAF). I would check the MAP sensor. As you open the throttle, its basically the increasing MAP that tells the ECM the engine is flowing more air.Fred
381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC engine management - 8 LS1 coils - 58mm TB - 78# injectors - 300-shot dry nitrous - TH400 - Gear Vendor O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motorComment
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alright, i went ahead and change the computer, it has seemed to help. it still stumbles a little but it will drive. i was going to have my buddy plug back into the car with is snap on code scanner and see what happens now. i haven't checked anything else yet i just haven't had them time. MartyComment
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