Possible Causes & Corrections
WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Check for the following items:
- Test fuel pressure. Refer to FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4.2L BRAVADA, ENVOY XL, TRAILBLAZER & TRAILBLAZER EXT article.
- Inspect Throttle Position (TP) sensor for binding or sticking. Voltage should increase at a steady rate as the throttle moves toward Wide Open Throttle (WOT) position.
- Inspect Manifold Absolute Pressure (MAP) sensor response and accuracy. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 4.2L BRAVADA, ENVOY XL, TRAILBLAZER & TRAILBLAZER EXT article.
- Test for water contamination in fuel.
- Test canister purge system for proper operation.
- Perform fuel injector coil test. Refer to FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 4.2L BRAVADA, ENVOY XL, TRAILBLAZER & TRAILBLAZER EXT article.
- Perform fuel injector balance test. Refer to FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 4.2L BRAVADA, ENVOY XL, TRAILBLAZER & TRAILBLAZER EXT article.
- Test for low fuel pressure after a cold start or during a moderate or full throttle acceleration.
- Inspect for fouled spark plugs.
- Inspect for proper ignition system performance.
- Search for Service Bulletins for calibration updates.
- Test generator output voltage.
- Inspect for a restricted exhaust.