I've only come across a high idle that set the code once. FSM's pointed us toward the IAC wiring etc and testing the connections from IAC valve to PCM. That resulted in nothing but teaching the guy how to check wiring. Then I took the cruise control and throttle cables off the TB. Fired up and it idled perfectly. This led me to look closer at the cables and how they are coiled on the strut tower. Wiggled them a little to ensure they were sitting right. Hooked them back up and magic, car has idled perfectly since.
I'm not conviced that is your issue though since yours tries to stall and catches itself etc. That does sound like the IAC is fighting to keep the engine running.
