Diagnostic Aids
- 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.
- Using a scan tool, review the Failure Records. If an intermittent condition is suspected, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.1L CENTURY, GRAND PRIX & MALIBU article.