I believe it is equipped with VVT, have its solenoid checked, clean it and its port of any slugde if any found retest. When problem occurs, lightly tap the solenoid with a rod or small mallet, do not use force. If the idling stabilizes suddenly, the solenoid is bad and sticking intermittently, which might not trigger any trouble codes.
If VVT solenoid is not the cause, check the valve clearance and adjust if necessary.
Was the throttle body replaced by the dealer with a new part complete with IAC?
Thursday, March 7th, 2013 AT 12:49 PM