Occasionally my (when it still had the auto) would, upon starting it up cold, idle extremely low until you drove it for a little while (like 300rpm), I switched to a six speed and had a chip for it burned from pcmforless. The idle was way too low, so i mechanically idled it up (which made for an rough idle, due to the air distribution not being even, since it was coming through the blades instead of the iac passage). This worked for awhile, then again the idle got progressively worse. I finally broke down and bought a new iac (idle air control) valve, and I have driven for a couple hundred miles, but still it tries to idle at around 550 w/ the a/c off, and like 500 with it on. Sometimes when you first start it cold it tries to idle at like 400. Also, the idle is very surgey (i know that's not a real word) varying sometimes like 75 rpm or so (it bounces). The car still runs terrific, just not at idle. The idle is so low that it is causing the battery to discharge b/c the alt. is not spinning enough. Should i just have my computer reprogrammed to idle like 200 rpm higher maybe?


Any help/suggestions would be greatly appreciated, as i tried posting it in the lt1 section and got no responses

 

What idle speed did pcmforless set in the ECM? I doubt he would intentionally set it that low for an M6. I also doubt he would alter the table of idle speed vs. coolant temp. If its not set where you want it, have it reprogrammed. If its not idling where its set, could be a problem you need to fix. Have you checked the coolant temp sensor? Have you verified the IAC counts the ECM is asking for in response to the incorrrect idle? Have you verified that the IAC valve is getting a signal from the ECM?

 

how would i go about doing those things (i don't have autotap or anything like) thanks!!!

 

i borrowed a friend autoXray and it read that the desired idle was 0 during one scan, and 200 on another. What could be causing this???