GM Service Manual Online
For 1990-2009 cars only

Inspection/Test

Action

DEFINITION: Engine continues to run after key is turned OFF, but runs very rough. If engine runs smooth, check the ignition switch and adjustment.

Preliminary

    •  Refer to Intermittent Conditions before starting.
    •  Search for bulletins.

Fuel System

    •  Test the fuel system circuits for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis .
    •  Test for low fuel pressure. Refer to Fuel System Diagnosis .
    •  Test for faulty fuel injectors. Refer to Fuel Injector Balance Test with Special Tool , Fuel Injector Balance Test with Tech 2 , Fuel Injector Solenoid Coil Test test procedures.
    •  Inspect for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    •  Inspect for fuel in the pressure regulator vacuum hose.
    •  Ensure each injector harness is connected to the correct injector/cylinder.

Additional

Test for short between battery positive voltage and any of the ignition feed circuits. Refer to Wiring Repairs in Wiring Systems.