Diagnostic Aids

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.

Monitoring the fuel injector circuit status using a scan tool while moving the fuel injector harness may help to isolate an intermittent condition.
Performing the Fuel Injector Coil Test may help isolate an intermittent condition. See FUEL INJECTOR COIL TEST .
For an intermittent condition, see INTERMITTENTS in TROUBLESHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.