Diagnostic Aids
WARNING: This page is about a different car, the 2002 Pontiac Grand Prix, 2002 Chevrolet Malibu, and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
Inspect for the following conditions:
- High resistance in an IAC circuit.
- Restricted air intake system.
- Proper operation and installation of all air intake components.
- Collapsed, clogged, or loose air intake ducts.
- A clogged air filter.
- Proper operation of Mass Airflow Sensor (MAF), if equipped.
- A tampered with or damaged throttle stop screw.
- A tampered with or damaged throttle plate, throttle shaft, or throttle linkage.
- Objects blocking the IAC passage or throttle bore.
- Excessive deposits in the IAC passage or on the IAC pintle.
- Excessive deposits in the throttle bore or on the throttle plate.
- Vacuum leaks.
- A low or unstable idle condition could be caused by a non-IAC system problem that cannot be overcome by the IAC valve.
If the problem is determined to be intermittent, refer to INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.