Possible Causes & Corrections

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. Low compression can be caused by improper valve timing, faulty manifold gaskets, sticking or leaking valve. See MECHANICAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article.
• 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 ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article.
• Perform fuel injector balance test. See FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article.
• Check AIR system for proper operation, if applicable. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article.