My experience with IAC failure is as buzzard described, would start, would not idle. When I removed it, it was stuck (can't remember if it was stucked open or close).

Anyway, I realized now that you have it in the shop, wondering how well you know your mech, since as I stated, it's really not a big deal to remove it just to see and check the condition of the valve. This is discounting any possibility that there is electrical issue on the IAC and not just mechanical.