Diagnostic Aids

Check for throttle body damage or evidence of tampering. Check for proper installation and operation of MAF sensor. Check throttle body shaft and linkage for excessive binding. Check for vacuum leaks, faulty or improperly installed PCV valve. Check for clogging or restriction of IAC valve air passage. Check for excessive deposits on throttle body plate, throttle bore and IAC valve pintle. Check for vacuum leaks. Check for a skewed TP sensor. If low or unstable idle condition is non-IAC related, attempt to diagnose by symptom.

If problem is intermittent, see INTERMITTENT TROUBLE CODE DETERMINATION  under SELF-DIAGNOSTIC SYSTEM.