Possible Causes & Corrections
WARNING: This page is about a different car, the 2003 GMC Sierra and 2003 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Check the following items:
- Inspect ignition system.
- Check for crossfire between spark plugs, such as the distributor cap, spark plug wires, and proper routing of the plug wires.
- Check engine for low compression. See CYLINDER COMPRESSION PRESSURE under MECHANICAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 4.3L SIERRA & SILVERADO article. Low compression can be caused by improper valve timing, faulty manifold gaskets, sticking or leaking valve.
- Check intake and exhaust system for fresh air entering exhaust upstream of the catalytic converter or restrictions.
- Check fuel system performance. See FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4.3L SIERRA & SILVERADO article.
- Perform fuel injector balance test. See FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 4.3L SIERRA & SILVERADO article.
- Check AIR system for proper operation, if applicable. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article.