Hey guys. Here is my issue: ONLY when the car warms up it idles very high, like 2k, when I come to a complete stop it idles back down normally, one the car starts to roll (no throttle) it jumps back up to the high idle speed. When it is cold, it will barely idle until it starts to warm up. There is a happy medium of good idle speed after cold start but before operating temp.
Here are the specifics: 72 Nova, 2000 LS1 (camaro), 4L60, Painless harness, trick flow heads, FAST 90mm TB, FAST "grey plastic" intake.
By the way....i bought this car running and it has a 2nd IAC on a block on the core support. The hose runs to the intake behind the throttle body. If I take this off it will not start on its own. What is the purpose of 2 IAC's?
Thanks in advance!

 

I'd start with a log session.
A look at the tune would help w/ ID'ing the 2nd IAC.