GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2001 🢒 Bonneville 🢒 Engine 🢒 Engine Electrical 🢒 Surges/Chuggles

Checks

Action

DEFINITION: Engine power variation under steady throttle or cruise. Feels like the vehicle speeds up and slows down with no change in the accelerator pedal.

Preliminary
    • Refer to Important Preliminary Checks Before Starting in Symptoms - Engine Controls .
    • Refer to Visual Physical Checks in Symptoms - Engine Controls .
    • Ensure that the driver understands the transmission torque converter clutch (TCC) and the A/C compressor operation as explained in the owner's manual. Inform the customer about how the torque converter (TCC) and the A/C clutch operate.

Sensor/System
    • Check the heated oxygen sensors (HO2S). The heated oxygen sensors should respond quickly to different throttle positions. If not, check the HO2S for silicon or other contaminants from the fuel or the use of incorrect RTV sealant. The sensors may have a white powdery coating. Silicon contamination causes a high, but false, HO2S signal voltage (rich exhaust indication). The powertrain control module (PCM) will reduce the amount of fuel delivered to the engine, causing a severe driveability problem.
    • Check the mass air flow (MAF) sensor and the related wiring.
    • Check the exhaust gas recirculation (EGR) valve for a stuck open pintle.

Fuel System
    • Check the fuel pressure. Refer to Fuel System Diagnosis .
    • Check for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Ensure each injector harness is connected to the correct injector/cylinder. Refer to Fuel Injector Electrical Harness Removal from Rail .
    • 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 in DTC P0171 .

Ignition System
    • Check for the proper ignition voltage output using the following procedure:
       - Clip the J 26792 Spark Tester to engine ground.
       - Connect one end of a spark plug wire to the spark tester. Leave the other end of the spark plug wire connected 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 mate.

       - Inspect the spark plug wires for signs of arcing/cross firing, cracks, carbon tracking, spark 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 problem. Ignition components will arc to ground when a secondary component is malfunctioning.

       - Check for a malfunctioning ignition control module (ICM).
       - 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 plug 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.

Additional Checks
    • Check the TCC operation. Refer to Torque Converter Diagnosis in Automatic Transaxle-4T65-E.
    • Check the exhaust system for a possible restriction:
       - Inspect the exhaust system for any 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 .