When I start my car after it has sat for a few hours (long enough for the engine to get cold, but this problem doesn't occur when I first start it in the morning) and come to the first stop the idle sometimes bounces wildly between a near stall and about 1200 rpm. It settles out after a second or two and doesn't act up again. The IAC, throttle body, and MAF are all fine. A Consult-II diagnostic found the base idle to be set at 1125, and after the idle was adjusted to a proper 738 the problem was minimized but is still noticeable. What else could be a potential cause?