Fuel System
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 Pontiac Grand Prix, 2003 Pontiac Bonneville, 2003 Chevrolet Monte Carlo, 2003 Chevrolet Impala, and 2003 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
- Check system fuel pressure. See FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
- Check the fuel injectors. See FUEL INJECTOR COIL TEST and FUEL INJECTOR BALANCE TEST WITH TECH 2 under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
- Check for contaminated fuel. See ALCOHOL/CONTAMINANTS-IN-FUEL DIAGNOSIS WITHOUT SPECIAL TOOL or ALCOHOL/CONTAMINANTS-IN-FUEL DIAGNOSIS WITH SPECIAL TOOL under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
- Inspect items which can cause an engine to run rich (long term fuel trim significantly in the negative range). See DIAGNOSTIC AIDS for DTC P0172: FUEL TRIM SYSTEM RICH under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
- Inspect items that can cause an engine to run lean (long term fuel trim significantly in the positive range). See DIAGNOSTIC AIDS for DTC P0171: FUEL TRIM SYSTEM LEAN under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
- Inspect for fuel in the fuel pressure regulator vacuum hose.