Possible Causes & Corrections

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Savana, 2003 Chevrolet Silverado, and 2003 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.

Check for the following items:

Check fuel pressure. See FUEL SYSTEM PRESSURE TEST under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 6.0L CHEVY EXPRESS, SAVANA, SIERRA & SILVERADO - BI-FUEL & CNG article. Inspect for low pressure during moderate or full throttle acceleration. If fuel pressure drops less than specification, there is possibly a low or high pressure regulator fault or a fuel system restriction.
Test for proper EVAP purge system operation. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 6.0L CHEVY EXPRESS & SAVANA - BI-FUEL & CNG article DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 6.0L SILVERADO & SIERRA - BI-FUEL & CNG article.
Test for proper TP sensor operation. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 6.0L CHEVY EXPRESS & SAVANA - BI-FUEL & CNG article DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 6.0L SILVERADO & SIERRA - BI-FUEL & CNG article. A TP sensor that does not respond quickly and accurately to throttle plate movement may cause this symptom.
Test for proper MAP sensor operation. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 6.0L CHEVY EXPRESS & SAVANA - BI-FUEL & CNG article DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 6.0L SILVERADO & SIERRA - BI-FUEL & CNG article.
Test for proper secondary ignition system voltage output using Spark Tester (J-26792).
Inspect for fouled spark plugs. If fouled spark plugs are fouled, repair cause of fouling.
Test for faulty spark plug wires.
Test for an open ignition system ground, if equipped.
Review service bulletins for AF ECM or PCM programming updates.
Inspect for manifold or air induction system leaks.
Test for proper generator operation.