Diagnostic Aids

WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.

Fuel contamination, such as water and alcohol, will affect the fuel trim.
The system will go rich if the injectors are supplying too much fuel.
Review the Failure Records with a scan tool. If intermittent condition is suspected, refer to INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.