GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2002 🢒 Sunfire 🢒 Engine 🢒 Engine Controls - 2.2L (LN2) 🢒 Lack of Power, Sluggishness, or Sponginess

Lack of Power, Sluggishness or Sponginess

Checks

Action

DEFINITION: The engine delivers less than expected power. There is little or no increase in the speed when the accelerator pedal is pushed down part way.

Preliminary Checks
    • Refer to Symptoms - Engine Controls .
    • Search for the service bulletins.
    • Compare the customer's vehicle to a similar vehicle. Ensure that the customer's vehicle has an actual problem.
    • Inspect the air cleaner filter for dirt or being plugged.

Fuel System Checks
    • Inspect the system fuel pressure. Refer to Fuel System Diagnosis .
    • Inspect the fuel injectors. Refer to Fuel Injector Balance Test with Special Tool or Fuel Injector Balance Test with Tech 2 .
    • Inspect for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Inspect the items which can cause an engine to run rich, where long term fuel trim is significantly in the negative range. Refer to Diagnostic Aids for DTC P0172 .
    • Inspect the items that can cause an engine to run lean, where long term fuel trim is significantly in the positive range. Refer to Diagnostic Aids for DTC P0171 .

Sensor/System
    • Use a scan tool in order to monitor the knock system (KS) system for excessive spark retard activity. Refer to DTC P0325 .
    • Ensure proper operation of the manifold absolute pressure (MAP) sensor.
    • Ensure proper operation of the throttle position (TP) sensor.
    • Inspect for a restricted air intake system.

Ignition System
    • Ensure proper ignition voltage output with the J 26792 Spark Tester or equivalent.
    • Inspect the spark plugs for the following conditions:
       - Wet or fuel-fouled spark plugs
       - Cracks on the spark plugs
       - Wear
       - Improper spark plug gap
       - Burned electrodes or heavy deposits
    • If the spark plugs are fuel or oil-fouled, determine the cause of the fouling before replacing the spark plugs.
    • Inspect the ignition control module (ICM) for proper ground connection.
    • Inspect the ignition coils for cracks or carbon tracking.
    • Inspect the spark plug wires for proper resistance and condition.

Engine Mechanical
    • Inspect the engine for the following engine mechanical problems:
       - Low compression
       - Correct valve timing
       - A leaking cylinder head gasket
       - A worn or an incorrect camshaft
    • Refer to Diagnostic Starting Point - Engine Mechanical in Engine Mechanical 2.2L.

Additional Checks
    • Ensure proper operation of the torque converter clutch (TCC). Refer to Torque Converter Diagnosis for a 3T40 or DTC P0742 for a 4T40 in Automatic Transaxle Diagnosis.
    • Inspect the exhaust system for a possible restriction:
       - Inspect the exhaust system for damaged or for possible collapsed pipes.
       - Inspect the muffler for heat distress or for possible internal failure.
       - Inspect for a possible plugged three-way catalytic converter (TWC). Refer to Restricted Exhaust in Engine Exhaust.
    • Inspect the vacuum lines for kinks or for leaks.
    • Inspect the generator output voltage. Repair the generator if the output voltage is less than 11 volts, or more than 16 volts.
    • Inspect the air conditioning (A/C) system operation. The A/C clutch should cut out at the wide open throttle (WOT) position.
    • If all procedures have been completed and no malfunctions have been found, review and inspect the following items:
       - All electrical connections within the suspected circuit and/or systems.
       - The scan tool data. Refer to Scan Tool Data List .