Yep, that's the problem, a hanging idle, especially when it's cold - any fixes? This is on my new ride, a 2004 Mach 1. I just got done installing (and then removing) an IAC restrictor plate (homemade gimmick, using two holes, one was the standard size, the second one, on the pass side of the IAC, was smaller, about 9/32", (all cut and drilled as described in an article here on StangNet). It seemed to drop the idle quicker in between shifts, but the idle, both cold and warm, was worse than ever...hanging around 1500 RPMS!
Help!
Help!