GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1998 🢒 Skylark 🢒 Engine 🢒 Engine Controls - 2.4L 🢒 Lack of Power, Sluggishness, or Sponginess

Lack of Power, Sluggish or Spongy

Checks

Action

Definition: Engine delivers less than expected power. Little or no increase in speed when the accelerator pedal is pushed down part way.

Preliminary Checks
    • Refer to Symptoms .
    • Search for service bulletins.
    • Check and compare the customers vehicle to a similar vehicle. Make sure the customers vehicle has an actual problem.
    • Check the air cleaner filter for dirt or being plugged.

Fuel System Checks
    • Check the system fuel pressure. Refer to Fuel System Diagnosis .
    • Check the fuel injectors. Refer to Fuel Injector Balance Test .
    • Check for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Check items which can cause an engine to run rich (long term fuel trim is significantly in the negative range). Refer to DTC P0172 Fuel Trim System Rich .
    • Check items that can cause an engine to run lean (long term fuel trim is significantly in the positive range). Refer to DTC P0171 Fuel Trim System Lean .

Sensor/System
    • Using a scan tool, monitor KS system for excessive spark retard activity.
    • Check for proper operation of the MAP sensor.
    • Check for proper operation of the TP sensor.
    • Check the EGR system for proper operation.
    •  Check for a restricted air intake system.

Ignition System
    • Check for proper ignition voltage output with the spark plug jumper wires J 36012-A and spark tester J 26792 .
    • Check 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, the cause of the fouling must be determined before replacing the spark plugs.
    • Check the ignition control module (ICM) for proper ground connection.
    • Check the ignition coils for cracks or carbon tracking.

Engine Mechanical
    • Check the engine for the following engine mechanical problems:
       - Check for low compression.
       - Check for correct valve timing.
       - Check for leaking cylinder head gasket.
       - Check for a worn or a incorrect camshaft.
    • Refer to Base Engine Misfire Diagnosis in Engine Mechanical.

Additional Checks
    • Check for proper operation of the TCC. Refer to Torque Converter Clutch Pulse Width Modulation Solenoid Circuit Electrical Check in Automatic Transaxle.
    • Check 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.
       - Check for possible plugged Three-Way catalytic converter. Refer to Restricted Exhaust System Check .
    • Check the vacuum lines for kinks or leaks.
    • Check the generator output voltage. Repair the generator if the output voltage is less than 11 volts or more than 16 volts.
    • Check the 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 not been found, review and inspect the following items:
       - Visually and physically inspect all electrical connections within the suspected circuit and/or systems.
       - Check scan tool data.