GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2006 🢒 Lucerne 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Lack of Power, Sluggishness, or Sponginess

Inspection/Test

Action

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

Sensor/System
    • Inspect the knock system (KS) for excessive spark retard.
    • Inspect the exhaust gas recirculation (EGR) system for proper operation.
    • Inspect for contaminated oxygen sensor.

Fuel System
    •  Test the fuel system for correct operation, restriction, volume, and pressure. Refer to Fuel System Diagnosis .
    • Test for proper operation of the fuel injectors. Refer to Fuel Injector Diagnosis .
    • Test for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Inspect the throttle body for coking. Refer to Throttle Body Inspection and Cleaning .
    • Inspect for lean or rich conditions. Refer to DTC P0171, P0172, P0174 or P0175 Conditions for Running the DTC. Refer to DTC P0171 or P0172 or DTC P0174 or P0175 .

Ignition System
    • Inspect for proper ignition system operation. Refer to Electronic Ignition (EI) System Diagnosis .
    • Inspect the spark plugs. Refer to Spark Plug Inspection .
    • Inspect the spark plugs for correct application. Refer to Ignition System Specifications .
    • Inspect for damaged ignition coils within the ignition coil module assemblies.
    • Inspect for damaged or misaligned spark plug boots.
    • Inspect for proper connections at each ignition module assembly.

Engine Mechanical
    • Inspect the engine mechanical for oil consumption, correct engine compression, and correct base engine timing. Refer to Symptoms - Engine Mechanical .
    • Inspect for incorrect basic engine parts. Inspect the following:
       - Camshafts
       - Cylinder heads
       - Pistons, etc.

Additional Inspections
    • Inspect for a restricted air intake system.
    • Inspect for a dirty or restricted air filter.
    • Inspect the exhaust system for possible restrictions. Refer to Restricted Exhaust .
    • Inspect the engine electrical system for proper operation. Refer to Charging System Test .
    • Inspect for proper torque converter clutch (TCC) operation. Refer to Torque Converter Diagnosis .
    • Inspect for conditions that cause the engine torque management system to reduce engine power.