Possible Causes & Corrections

Check for the following items:

• Check fuel pressure. See FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP 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 - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article.
• Check the canister purge system for proper operation.
• Perform fuel injector coil test. See FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 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.
• Test for low fuel pressure after a cold start or during a moderate or full throttle acceleration.
• Check for damaged spark plug wires.
• 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. See EXHAUST SYSTEM BACKPRESSURE under CYLINDER MECHANICAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article.