Additional Checks
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 exhaust system for possible restrictions. Inspect for the following:
- Inspect exhaust system for damaged or collapsed pipes.
- Inspect mufflers for heat distress or possible internal failure.
- For possible plugged 3-way catalytic converter. See EXHAUST SYSTEM CHECK under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
- An engine miss condition can be caused by Electromagnetic Interference (EMI) on the reference circuit. EMI can usually be detected by monitoring engine RPM with a scan tool. A sudden increase in RPM with little change in actual engine RPM change, indicates EMI is present. If a condition exists, inspect routing of secondary ignition wires, high voltage components (near ignition control circuits).
- Inspect for intake and exhaust manifold passages for casting flash.
- Inspect for faulty motor mounts.