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 a clogged air filter.
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 engine compression. Check for incorrect valve timing, bent push rods, broken valve springs or worn camshaft lobes.
Check Park Neutral Position (PNP) switch circuit. Ensure PNP switch is properly adjusted.
Check Torque Converter Clutch (TCC) system for proper operation.
Check for dragging brakes.
Check cooling system thermostat for proper heat range and operation.
Ensure correct initial ignition timing.
Remove spark plugs and check for wet/fouled spark plugs, cracks, improper gap, burned electrodes or heavy carbon deposits.
Check fuel system for incorrect fuel pressure. See BASIC FUEL SYSTEM CHECKS 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 injector harness locations. Ensure injectors are connected to correct injector/cylinder according to firing order.
Check Engine Coolant Temperature (ECT) sensor for shift in calibration. See appropriate SENSOR OPERATING RANGE CHARTS article.
Check PCV system for proper operation.
Check for proper Crankshaft Position (CKP) and Camshaft Position (CMP) sensor resistance.
Check for fuel in pressure regulator vacuum hose. If fuel is present, replace regulator.
Check for items that cause the engine to run rich.
Check the Knock System (KS) for excessive spark retard.
Ensure speedometer is properly calibrated.
Ensure A/C system is not always on.
Check for incorrect tire pressure.
Check for uneven or excessive tire wear from suspension misalignment.
Check with operator to see if vehicle is operated under excessive acceleration or is heavily loaded.