Hi

Have a 1989 5.7 gta trans Am that drives ok but when its hot the idle goes up and Down and in drive its almost stalls.have tryed the adjustment with the clips in the aldl but when i remove the connecter from the IAC the car wont start,Anybody know why??

Tanks Claus

 

have you checked you tps?

 

My 87 tpi also dose the same thing , runs like there no tommrow but stalls if a leave it in drive and stop . My car is very not original was a V-6 manual now it's two import 305

 

Same problem here. Just replaced the injectors with 22lb South Bay Bosch III's. Fuel pressure is 50 peak 35 idle new filter iac and TPS. TPS set at .55v. Runs great but rich when cold but if the temp gets over 95 out everything falls to ****. Won't idle and if it does idle it bounces from 500 to 1200 rpm. Acts fuel starved but every time I test fuel pressure it tests fine. Original pump has 92k miles on it but almost 30 years old of course. Oh and new fuel pressure reg. figured while I was at it with the injectors I might as well replace it. Vac system is solid, plenum is tight... I'm just confused.

 

hello ok i have now replaced the IAC valve and there is no diff. car still runs low in idle,but i have tryed to adj. the TPS with the engine running and gear in N. I can adj. the TPS so the engine runs great in idle and drives great but after some time the problem is back......any body know why??????

 

Try setting your TPS to spec and running it to wide open throttle. .54 to .56v. If while your opening the throttle the voltage doesn't increase smoothly... May be a bad TPS. I saw this on another thread... Think it tops out around 4 volts, you may want to search around and confirm. If your TPS is ok you got me stumped. You also might check the wires to... On my car it runs close to the alternator and I have pinched the wires to the TPS before.

 

Cold you have put runners on wrong side? Also wasn't 89 first year of those junk multec injectors?

 

does it jump or miss in gear or at idle? when it does die whats the rpm at?

 

It's worse with the ac on or in gear. Really falls to **** if idling with ac on. I warmed up the car and was messing with it this morning. I pulled the plug on the MAF the car smoothed out. It was a reman and I think it's bad after only 4 months. I'll know for sure tomorrow morning when the new one shows up. Thank god for warranty. When it dies it's around 400 rpm before it gives up.

 

what happened with the new MAF?

 

Oh I got it, finally smoothed out a bit. Still not right. Come to find out the distributor is shot. I have a frankencar 87 power plant in a 85 so the distributor is 85 rest is 87. Lots of confusion but it works. I'm suspecting pickup coil and a bad gear possibly timing chain but not as likely. Motor has 6000 miles on it distributor has 92000 so it makes sense that it's my problem. I'll know for sure Friday. But long story short my main idle problem was MAF.

 

@clause290373

Also, there is a way to adjust your iac valve. Plug in the iac, turn the car on, unplug the iac, turn the car off, than plug the iac back in and your done. Sounds dumb but it works. It tells the computer where the closed position is. When you turn the key on it pushes the plunger into the throttle body and the plugged in and unplugged pattern sets the commuters closed position properly. There is a video on YouTube if I'm not making any sense.

 

do not buy a re-man MAF!!!!! buy a new one,trust me ,I went thru 7 pos MAFs from autozone before I got wise and bought a new one. it fixed mine and so far its staying fixed

 

Ya, damage is done have a reman. Regret it already, saving my pennies for a new one. I work at autozone so it was on the shelf. Going to get a new one from "o-really's" but so far the reman is holding. My problem now is the distributor so it's kind of one catastrophe at a time till it's fixed. If it holds till I can get a new one I'm going to keep it as a spare.

 

Got some inj from SouthBay and the car drives and idles fine now