I have a 91 Z28 that I just got finished putting exhaust on. Started car last nite....idled fine. Got up this morning, made sure all bolts etc were tight....drove the car, and it ran fine. It was idling a "little" rough but I thought that might be because the plugs havent been changed in about a year and the car itself had sit for a while. I checked the TPS sensor and it was ok(.56volts). SO I decided to adjust the IAC for minimum air. I put the jumper in the ALDL waited about 45sec and started the car.....it idled about 500rpm but was like it was searching for an idle speed.....so I set the idle to about 600rpm and shut it off. I disconnected the neg battery cable and waited about 10min and reconnected it. It started fine....but idles funny now...like it cant find its idle speed. I checked the TPS again and it was about .576 volts....so I reset it to .55 volts. I did the trick with the neg batt cable again....waited about 15min and reset it. Now the car will barely idle. I have ruled out the 02 sensor because I just replaced it about a day ago while I was doing the exhaust. Could it just be the plugs are fouled? The wires and cap are a little over a year old(Accel cap and 8.8 wires). The ignition module and coil are all about the same age. Is there anyway to check the IAC to see if its bad??? Im stuck...any input would be greatly appreciated. Thanks in advance...........:hail:

 

If you are trying to adjust your minimum idle speed, there is a set procedure for doing it. Vader posted the proper procedure for doing it in another post in response to a members question concerning a similar problem. I will see if I can locate this post and post it for you.

Try this link!!

http://www.thirdgen.org/techbb2/show...threadid=93405


The Trickster!!!!!!!!!!!!!

 

I knew the procedure(I thought)....but I didnt disconnect my est timing plug first.....that may be why...Im also gonna clean the IAC and see if that helps...

 

sounds like the same problem i'm having with my car i was just wondering if you ever found out what the problem was?