Subject: Re: Another rough idle by CFI-EFI on 2009/7/14 15:07:01
Quote:
DaleD wrote: My car is running pretty well, but once it warms up, the idle seems to go low enough to cause it to idle rough. When cold it idles at 700. Once it heats up, it drops to 600, and will start to hunt down to 500. When it gets to that point, it starts chugging. Any ideas?
With only these symptoms, it isn't fuel pressure, fuel pump, or fuel injectors. Vacuum leaks DO cause problems with the idle, but the additional air from a vacuum leak makes it idle faster, not slower. Resetting the IAC is only needed when installing or reinstalling the IAC. The IAC will self reset if the procedure isn't performed. It isn't a tune up or maintenance operation. The low idle speed indicates a lack of sufficient air. Because you report the idle speed changes as the engine warms up (as it should) it seems the IAC is working. You should be looking at why the engine isn't getting enough air for a proper idle speed. I would start by checking the IAC passage in the TB for a restriction, such as a carbon build up.
