GM Service Manual Online
For 1990-2009 cars only

Surges/Chuggles Petrol

Checks

Action

DEFINITION: The engine has a power variation under a steady throttle or cruise. The vehicle feels as if speeds up and slows down with no movement of the accelerator pedal.

Preliminary Checks

    • Refer to Important Preliminary Checks in Symptoms - Engine Controls .
    • Ensure the vehicle operator understands the transmissions torque converter clutch (TCC) operation, if equipped.
    • Ensure the vehicle operator understands the A/C compressor clutch operation, if equipped.

Sensor Checks

    • Test for correct operation of the vehicle speed sensor (VSS).
    • Test for correct operation and performance of the oxygen sensor.

Fuel System Checks

    • Inspect for a lean or rich engine condition.
        Using a scan tool observe the oxygen sensor output while operating the vehicle under the symptom condition.
    • Test for correct fuel system pressures. Refer to Fuel System Diagnosis .
    • Inspect for correct operation of the LPG fuel injectors. Refer to:
    • Make sure that the manual shut-off valve is fully open.
    • Inspect for restricted LPG lock-offs or filter. Refer to and Fuel Filter Replacement .

Surges/Chuggles LPG

Checks

Action

DEFINITION: The engine has a power variation under a steady throttle or cruise. The vehicle feels as if speeds up and slows down with no movement of the accelerator pedal.

Preliminary Checks

    • Refer to Important Preliminary Checks in Symptoms - Engine Controls .
    • Ensure the vehicle operator understands the transmissions torque converter clutch (TCC) operation, if equipped.
    • Ensure the vehicle operator understands the A/C compressor clutch operation, if equipped.

Sensor Checks

    • Test for correct operation of the vehicle speed sensor (VSS).
    • Test for correct operation and performance of the oxygen sensor.

Fuel System Checks

    • Inspect for a lean or rich engine condition.
        Using a scan tool observe the oxygen sensor output while operating the vehicle under the symptom condition.
    • Test for correct fuel system pressures. Refer to Fuel System Diagnosis .
    • Inspect for correct operation of the LPG fuel injectors. Refer to:
    • Make sure that the manual shut-off valve is fully open.
    • Inspect for restricted LPG lock-offs or filter. Refer to and Fuel Filter Replacement .