Diagnostic Aids
WARNING: This page is about a different car, the 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, 2003 Chevrolet Monte Carlo, and 2003 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
Inspect for the following conditions:
- A high resistance in an IAC control circuit.
- A restricted air intake system.
- Proper operation and installation of all air intake components.
- Any collapsed, clogged, or loose air intake ducts.
- A clogged air filter.
- Proper operation of the MAF sensor, if equipped.
- A tampered with or damaged throttle stop screw.
- A tampered with or damaged throttle plate, throttle shaft, or throttle linkage.
- Any objects blocking the IAC passage or throttle bore.
- Any excessive deposits in the IAC passage or on the IAC pintle.
- Any excessive deposits in the throttle bore or on the throttle plate.
- Any vacuum leaks.
- A low or unstable idle condition could be caused by a non-IAC system problem that can not be overcome by the IAC valve.
If the problem is determined to be intermittent, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article.