Diagnostic Aids

Check for the following conditions:

• Correct PCV valve, properly installed and proper operation of PCV valve.
• Proper operation and installation of all air intake components.
• Proper installation and operation of mass airflow sensor.
• A tampered with or damaged throttle stop screw.
• A tampered with or damaged throttle plate, throttle shaft, throttle linkage, or cruise control linkage, if equipped.
• A skewed high TP sensor.
• Excessive deposits in IAC passage or on IAC pintle.
• Excessive deposits in throttle bore or on throttle plate.
• Vacuum leaks. A high or unstable idle condition could be caused by a non-IAC system problem that cannot be overcome by IAC valve.
• If condition is determined to be intermittent, see INTERMITTENT TROUBLE CODE DETERMINATION  under SELF-DIAGNOSTIC SYSTEM.