Ive got a 1990 rs camaro with the 3.1 when I bought it had no problems with the way it ran some time goes by and it starts idleing really high so I put a new iac valve in and a new throttle body gasket in and that worked for awhile but now its doing it again and I cant figure it out for the life of me when I start it it jumps right to prob around 3 to 3500rpm so I put it in gear right away if anybody has any ideas what to do or check please help cause its extremly irratating

Brian:

Here'* a few things you might want to check.

Did you reset the computer and do a re-learn after you changed the IAC? Also, check the routing and condition of vacuum lines; it'* possible something came loose or a line cracked while you were under there. It probably wouldn't hurt to check for a sticking throttle body, or a dirty MAF. Make absolutely sure if you clean your MAF sensor, *ONLY* use MAF Sensor Cleaner, and make sure it has air-dried completely before starting the car.

The MAF may be an issue too, try disconnecting it (ignition off) and start it and see what happens. Usually a MAF failure will cause rough idle or no-start, but this is an easy way to rule that out.

Good luck!

a maf failure or any other that lets it run will cause lights. is there any check engine codes?
definitely recheck all the vacuum lines might be cracked looking but dont leak till you mess with them then wont seal. also did you clean the iac seat and carbon out of the tb?

Cool thanks for the tips I'll try it out and get back

I hecked my engine codes and got a code 23 wich is air intake temp sensor out of range, low. Could that also contribute to my idle problems.

it will. the pcm bases your a/f ratio on the temp, and if its wrong it will run bad