Diagnostic Aids

WARNING: This page is about a different car, the 2003 Pontiac Aztek and 2003 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The system will go lean if an injector is not supplying enough fuel.
A lean condition could be present during high fuel demand due to a fuel pump that does not pump enough fuel.
Fuel contamination, such as water and alcohol will effect the fuel trim.
Use a scan tool in order to review the Failure Records. If an intermittent condition is suspected, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.4L AZTEK & RENDEZVOUS article.