What are the odds of this happening! I too believe mine is not a bad IAC. It does not throw a code consistently. Once in a few months maybe, and not IAC related sometimes. I will check my coolant level. If it is the case, the coolant level should be low.

I can remember this problem also starting around the time I did a radiator flush, but it went away for a couple of years.

Thanks.

my issues turned out to be voltage related, my upper radiator inlet and hose were spraying coolant into the alternator, thus causing a short to ground, at idle there was no load so the car ran, but in gear and trying to drive, the alt couldnt handle the stress, i would sit and watch coolant drip and the alt, arc and the car would idle down, i replaced both and no issues since.