GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2000 🢒 Sonoma Pickup - 2WD 🢒 Engine 🢒 Engine Controls - 2.2L (L43) 🢒 Lack of Power, Sluggishness, or Sponginess

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 restrictions.

Fuel System Checks
    • Check the system fuel pressure. Refer to Fuel System Diagnosis .
    • Check the fuel injectors. Refer to Fuel Injector Balance Test .
    • Check items which can cause an engine to run rich--Long Term FT is significantly in the negative range. Refer to Diagnostic Aids for DTC P0172 Fuel Trim System Rich .
    • Check items that can cause an engine to run lean--Long Term FT is significantly in the positive range. Refer to Diagnostic Aids for DTC P0171 Fuel Trim System Lean .

Sensor/System
    • Use a scan tool in order to monitor KS system for excessive spark retard activity. Refer to DTC P0325 Knock Sensor (KS) Circuit .
    • Check for proper operation of the MAP sensor. Refer to Manifold Absolute Pressure Sensor Output Diagnosis .
    • Check for proper operation of the TP sensor.
    • Check for a restricted air intake system.

Ignition System
    • Check for proper ignition voltage output with the J 26792 .
    • Check the spark plugs for the following conditions:
       - Wet or fuel fouled
       - Cracks
       - 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.
    • Check the spark plug wires for proper resistance and condition.

Engine Mechanical
    • Check the engine for the following engine mechanical conditions:
       - Low compression--Refer to Engine Compression Test in Engine Mechanical.
       - Correct valve timing
       - Leaking cylinder head gasket
       - Worn or a incorrect camshaft
    • Refer to the appropriate diagnostic procedures in Engine Mechanical.

Additional Checks
    • Check for proper operation of the torque converter clutch (TCC). Refer to Automatic Transmission Diagnosis.
    • Check the exhaust system for a possible restriction:
       - The exhaust system for damaged or for possible collapsed pipes.
       - The muffler for heat distress or for possible internal failure.
       - Possible plugged three-way catalytic converter--Refer to Restricted Exhaust System Check .
    • Check the generator output voltage. Repair the generator if the output voltage is less than 11.0 volts or more than 16.0 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 been found, review and inspect the following items:
       - All electrical connections within the suspected circuit and/or systems
       - Scan tool data