okay - for a while now car has had a wierd idle where it would either idle too low(500) or too high(1400). id just have to restart car and it would randomly be one or other.

This winter installed cam and ton of other parts. Had a madZ tune and had my idle set to 850. Since the install slowly the idle has gotten worse to the point where when i start my car i have to give it a good rev and the idle will sit about 1100. If i drive for a while idle will become 1400. If i dont rev the car when i start it idle will sit at about 500 and be impossible to drive.

ive been checking vacumn lines, attempting to adjust the blades to no avail.

well driving around yesterday threw a 1509 code "Idle Speed High", cleared it and got it again later that night.... so that leads me to believe the IAC has kicked the bucket seeing how ive checked vacumn and cleaned the TB to make sure it isnt sticking.

so.. would the wierd idle issues be explained by an IAC going bad?

 

During the test for that problem, the PCM uses MAF results while the engine is being driven. Either the IAC is a problem or the MAF is a problem.

I suppose it's a longshot that the IAC port is plugged but that should produce consistant results.

 

had the same problem on my Z a while back, didnt have a cam or any major mods at the time, but i'd take a look at your EGR valve that fixed everything for me, good luck

 

EGR has been programmed out and is off the car- so doubt its that - im gonna just replace the IAC and go from there

 

EGR has been programmed out and is off the car- so doubt its that - im gonna just replace the IAC and go from there

 

What ended up happening? Mine has had similar problems also. I replaced my IAC
ran fine that night, but the next morning problems were still there.

 

well ... didnt replace it- i reset it following shoebox's instructions- then cleaned the TB real well and did a full tune up on car. ( had to install plugs for nitrous anyway )

well.. car runs 10x better... if i drive hard for a while idle will stick at 1300 or so when i come to a stop but after a bit it will settle down. so.. havent completly resolved and figure i wont till i get the new IAC in.. i just wanted to try and save the money first.


ha or if i get lazy and want the lope i just turn on my heater or ac or brake while turning and shell drop to about 200 lol...damn cam

sorry couldnt really help