90 Idle Problems

[fastLX50]

Ok here is what i have been dealing with. When i start the car sometimes it idles fine and then sometimes all of a sudden it will race up to 2000 RPM on its own. When i disconnect the IAC idles fine, as soon as i plug it back in idle races up again. I have two IAC valves tried them both and they both do it.
checked the TPS voltage and is good.
Any thoughts.

 

[jrichker]

Checklist”[/URL][/u] [/b]for help with all your idle/stall problems. You can guess at the problem and throw parts at it, or you can use the checklist to help you find the problem quickly and inexpensively. The checklist is right here in the Stangnet 5.0 Tech forum and you don’t have navigate to some other unknown web site. It‘s free and doesn’t cost anything: at last count there were more than 103,000 visits and still climbing

The quick and easy way to dump the codes is in there too, and all you need to do it is a paper clip! The first two posts contain all the fixes & updates. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.