223 Idle air control valve signal missing 233 Long term fuel trim at idle exceeded contol limits. These codes and the symptoms would lead too: Idle air valve electrical connection problem, remove the wiring connector and clean the contacts for a start. The fuel trim problem may be due to the problem with the idle air valve. I would remove the throttle body and the idle air valve and give them a clean with carb cleaner, also look for any air leaks into the induction system, the rubber elbows used on the vacuum pipe connections often leak. Once you have done this, clear the fault codes and see if any come back.