GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2001 🢒 Bonneville 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 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 Important Preliminary Checks Before Starting in Symptoms - Engine Controls .
    • Refer to Visual/Physical Checks in Symptoms - Engine Controls .
    • Search for bulletins.

Fuel System
    • Check the fuel pressure. Refer to Fuel System Diagnosis .
    • Check the fuel injectors. Refer to Fuel Injector Solenoid Coil 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 Diagnostic Aids for DTC P0172 .
    • Check items that can cause an engine to run lean (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 sensor (KS) system for excessive spark retard activity.
    • Check the EGR valve for a stuck open pintle. Refer to Exhaust Gas Recirculation Valve Replacement .
    • Check for a restricted intake duct or a dirty air cleaner element. Refer to Air Cleaner Element Replacement .
    • VIN 1 only: check for proper supercharger boost control operation. Refer to Boost Control System Diagnosis .

Ignition System
    • Use the following procedure in order to check for the proper ignition voltage output:
       - Clip the J 26792 Spark Tester to engine ground.
       - Connect one end of a spark plug wire to the spark tester. Connect the other end of the spark plug wire to the coil being tested.
       - Connect another spark plug wire between the remaining tower of the coil being tested and ground.
       - Crank the engine while observing the spark tester. A crisp blue spark should be observed.
       - Repeat the above steps for each coil.
    • If adequate spark is not present at the coils, check for the following conditions:
       - Inspect the coils for cracks, carbon tracking/arcing, or a resistance value outside the specified range.

Coil Secondary Resistance
5000-8000 ohms

   Important:: If carbon tracking is detected on any component, replace that component and it's mate.

       - Inspect the spark plug wires for signs of arcing/cross firing, cracks, carbon tracking, plug boot damage, pinching, incorrect routing, or a resistance value more than the specified value.

VIN 1 Spark Plug Wires Resistance
3280-4921 ohms per meter (1000-1500 ohms per foot)

VIN K Spark Plug Wires Resistance
3280-4921 ohms per meter (1000-1500 ohms per foot)

   Important: Spraying the secondary ignition wires with a light mist of water may help locate an intermittent condition. Ignition components will arc to ground when a secondary component is malfunctioning.

       - Check for a malfunctioning ignition control module.
       - Check the ignition system wiring for a loose ignition module feed, ground connection, or damaged system wiring.
    • Remove the spark plugs.
    • Inspect the spark plugs for the following conditions:
       - Check the spark plugs for fouling.
       - Check the spark plugs for cracks.

   Important:: If carbon tracking is detected on any component, replace that component and mate.

       - Check the spark plugs for signs of carbon tracking on the porcelain or arcing at the plug wire contract.
       - Check the spark plugs for incorrect gap. Refer to Maintenance Items in Maintenance and Lubrication.
       - Check the spark plugs for burned or damaged electrodes.
       - Check the spark plugs for an incorrect heat range. Refer to Maintenance Items in Maintenance and Lubrication.
    • If the spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.

Engine Mechanical
    • Check for excess oil in the combustion chambers and leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical.
    • Inspect for low cylinder compression. Refer to Cylinder Leakage Test in Engine Mechanical.
    • Inspect for incorrect engine parts, such as the following basic components:
       - The camshaft
       - The cylinder heads
       - The pistons, etc.
    •  Refer to Symptoms - Engine Mechanical in Engine Mechanical.

Additional Checks
    • Check the exhaust system for a possible restriction:
       - Inspect the exhaust system for damaged or collapsed pipes.
       - Inspect the muffler for heat distress or internal failure.
       - Check for a plugged 3-way catalytic converter. Refer to Restricted Exhaust .
    • Check for proper TCC operation. Refer to Torque Converter Diagnosis in Automatic Transaxle-4T65-E.