I have cleaned the IAC... and it still had a high idle. I replaced it with a new and the problem still persists. Just under 1000RPM when cold, after a short drive it hits 12-1500 and surges throwing my transmission shifting off. I thought it might be air in the coolant since I recently did timing belt-coolant, but I purged all air. I have no over heating issues and I get hot air from the vent when heat is on. I have no shorts in the plug. Can this VALVE ASSY., AIR ASSIST be the cause? Anyone please.