Ok i just bought a 1990 Iroc Z-28 with the 5.7L TPI. the car is great but it has one little annoying problem that i don't know what to do about. Ok the car starts up and idles a little high when cold which i figure is normal...then goes down after getting warm. But the problem is that when i put the car in reverse it goes into gear and idles fine..but if i press the gas just a tad it likes to die out and stall...if i just let it idle goin in reverse it won't stall...but just that little pressure of giving it gas makes it wanna die out and stall...Now if i just press it firmly and go it just goes and doesn't wanna stall at all...just when i give it a little bit of gas...It also does this in forward...it idles fine in gear...but when you give it a little bit of gas it likes to die out...it doesn't stall as much in forward though...but if you kinda start off quickly it won't stall and runs fine. The car runs and idles great but in those gears with a little bit of gas it likes to do that. Can you help me out a little bit?!?!?!?!!?!?!?

Thanks Lance

 

your problem could be a number of things. the first thing is and maybe the ceapest thing is, check and see if there is anything blocking your airflow, also check out the catalytic converter it migh be clogged or bad, i would take it out anyways. besides that i'm not totally sure

 

it wouldn't hurt to check the ignition system either. check you plugs, wires, coil, cap, and rotor and see if any need replacing. it may not fix your problem but they might need replacing anyways.


well you can always fix the problem by stomping hard on the throttle every time you wanna go somewhere

 

Electrical was what i was thinking along with what you had said...but i was also wondering if a fuel filter could be doing it or anything with the gas...it just seems like it doesn't get any gas at about 1000 RPM or something its weird....all help is appreciated thanks a lot guys...
Lance

 

I would start with a fuel pressure check...if that`s okay then move on to the throttle body and make sure the blades are clean with no coking around the edges..use throttle blade cleaner if they are dirty. If all of that is fine I would move on to check the TPS sensor..sometimes they will get a "flat spot" and voltage will not move or be delayed. Tune up is probably a good thing to do if it has not been done recently, new plugs and filters will most likely do, checking the ignition timing is also a given. Any one of these things can cause your problem...there are more items that will cause this also...namley the MAF sensor if you have one...when they foul you can bet there will be off idle problems

 

I'd check the throttle position sensor. I don't think that the "auto calibrating" TPS started until 1991. I'd set the TPS (assuming it is not auto calibrating) for .67 volts and start there. Also, check it with an analog volt meter to see if it has a dead spot just off idle, that could also be causing your problem.

My thoughts.

 

Off idle hesitation? Dirty throttlebody is the most likely culprit. Clean it up real good with some TB cleaner and a toothbrush and see if it doesn't help. Also clean the IAC ports while you're there.