Possible Causes & Corrections
WARNING: This page does not describe the selected car, but rather 34 other vehicles, including the 2002 Saturn Vue, 2002 Pontiac Montana, 2002 Pontiac Aztek, 2002 Oldsmobile Silhouette, and 2002 Oldsmobile Bravada. However, it is still accessible from the selected car via links, so may be relevant.
Check the following items:
- Check for engine vacuum leaks. Ensure engine is tuned to specifications.
- Inspect the Secondary Air Injection (AIR) system.
- Using Spark Tester (J-26792), check available output voltage of ignition coil.
- Check air induction system for restrictions or air leaks.
- Check exhaust system for restrictions, such as a damaged or collapsed pipe, muffler or catalytic converter. See EXHAUST SYSTEM BACKPRESSURE under MECHANICAL INSPECTION in appropriate BASIC DIAGNOSTIC PROCEDURES article.
- Check fuel injectors. Perform injector balance test. See FUEL INJECTOR BALANCE TEST under FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article.
- Check fuel system for incorrect fuel pressure. See BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
- Inspect that each injector harness is connected to the correct injector or cylinder according to the firing order.
- Check engine compression. Check for incorrect valve timing, bent push rods, broken valve springs or worn camshaft lobes.
- Check transmission shift solenoid system and Torque Converter Clutch (TCC) system for proper operation.
- Check for intermittent ignition system problem.
- Check intake and exhaust manifold passages for casting flash.
- Remove spark plugs and check for wet plugs, cracks, improper gap, burned electrodes or heavy carbon deposits. Also, check condition of spark plug wires. Spray spark plug wires with a fine mist of water to check for shorts.
- Ensure initial ignition timing is properly set.
- Ensure speedometer is properly calibrated.