I recently replaced LIM & TPS & had all codes cleared. A few days later the engine light came on. Had it scanned & recieved code p0507. The car was running still running good so I drove it to work the next day. When I started it up the idle was high--2k rpm. I drove it about 2 miles & when I came to a stop sign, I turned it off & restarted it. The idle returned to normal. Thhis afternoon I started it & the idle went to 3k-3.5k rpm. I drove it a short distance then cut it off. It returned to normal. Is it the IAC? Is there a test for this?

Did you by chance see this thread https://www.gmforum.com/t279317/ for trouble shooting?

I'll check it out. Thanks!

I didn't see anything about high idle. What'* the best way to check for vacuum leaks?

You can spray carb cleaner around the vacuum lines while the engine is running. If the RPM goes up, you found a leak.

Duh--I knew that. I'm brain dead tonight.
thanks