Diagnostic Aids

WARNING: This page is about a different car, the 2003 Oldsmobile Aurora. 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.
A clogged air filter.
Proper operation of the mass air flow sensor.
A tampered or damaged throttle stop screw.
A tampered or damaged throttle plate, throttle shaft, or throttle linkage.
Objects blocking IAC passage or throttle bore.
Excessive deposits in IAC passage or on IAC pintle.
Excessive deposits in throttle bore or on throttle plate.
Vacuum leaks.
A low or unstable idle condition could be caused by a non-IAC system problem that cannot be overcome by IAC valve. See SYMPTOMS in TROUBLE SHOOTING - NO CODES - 4.0L AURORA article.