High idle
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High idle Hey everyone, I have a 99 camaro with basic bolt ons. Recently it started to idle at 1200 rpms, and now with the ac or heat on it idles at 1800 rpms. I tried replacing the IAC valve, but it's still idling high. Any ideas would help.
Start looking for vacuum leaks. PCV hoses are common places. Also check small vacuum lines on back of intake. I had the same problem on my car and turned out the PO got happy when he ported the throttle body but it didn't affect the idle until months later somehow. Anyway, you can also check tps reading. Possibly clean MAF sensor if you just want to feel like you did something lol. Has it set a DTC yet?
If you have access to a scanner check your IAC count at idle and TPS voltage.
Look for desired idle and actual idle.
If the IAC count is 0 you have a vacuum leak somewhere. I'm going to assume you haven't messed with the idle set screw any. I bought a used throttle body when I put my car back to stock and it idled at 1400 or so. Ended up being the guy I bought it from had opened the T/B blade quite a bit. If you haven't adjusted the T/B this won't your problem, just throwing it out there.
Another thing I just thought of is make sure the throttle cable hasn't come out of adjustment preventing the throttle to close all the way.
Look for desired idle and actual idle.
If the IAC count is 0 you have a vacuum leak somewhere. I'm going to assume you haven't messed with the idle set screw any. I bought a used throttle body when I put my car back to stock and it idled at 1400 or so. Ended up being the guy I bought it from had opened the T/B blade quite a bit. If you haven't adjusted the T/B this won't your problem, just throwing it out there.
Another thing I just thought of is make sure the throttle cable hasn't come out of adjustment preventing the throttle to close all the way.
