GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1999 🢒 Intrigue 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 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.
    • Refer to Visual/Physical Checks
    • Search for bulletins.
    • Be sure driver understands the transmission torque converter (TCC) clutch, and A/C compressor operation as explained in the owner's manual. Inform the customer about how TCC and the A/C clutch operates.

Sensor/System
    • Test the heated oxygen sensors (HO2S). The HO2S should respond quickly to different throttle positions. If the sensors do not respond properly, inspect the HO2S for silicon or other contaminants from fuel or use of improper RTV sealant. The sensors may have a white powdery coating. Silicon contamination causes a high, but false, HO2S signal voltage. The PCM reduces the amount of fuel delivered to the engine causing a severe driveability problem. Refer to Information Sensors/Switches Description .
    • Inspect the mass air flow (MAF) sensor and the related wiring.
    • Test the EGR system for proper operation. Refer to Exhaust Gas Recirculation (EGR) System Description .

Fuel System
    • Test the fuel pressure. Refer to Fuel System Pressure Test .
    • Test for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Test any items which can cause an engine to run rich. Refer to DTC P0172 Fuel Trim System Rich .
    • Test any items that can cause an engine to run lean. Refer to DTC P0171 Fuel Trim System Lean .

Ignition System
    • Use the following procedure in order to test 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. Leave the other end of the spark plug wire connected to the coil being tested.
       - Connect one end of another spark plug wire to the other coil tower. Connect the other end of the spark plug wire to ground.
       - Crank the engine while observing the spark tester. Spark should be observed.
       - Repeat the above steps for each coil.
    • If adequate spark is not present at the coils, inspect for the following conditions:
       - Inspect the coils for cracks, carbon tracking/arcing, or a resistance value outside the 5000 - 8000 ohms range.
       - Inspect the spark plug wires for signs of arcing/cross firing, cracks, carbon tracking, plug boot damage, pinched wires, improper routing, or an improper resistance value. The resistance should measure 600 ohms per ft. (1968 ohms per meter).

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

       - Inspect or test for a defective module.
       - Inspect the ignition system wiring for a loose ignition module feed or ground connection, or damaged system wiring.
    • Remove the spark plugs and inspect for the following:
       - Fouled plugs
       - Cracks
       - Wear
       - Improper gap
       - Burned or damaged electrodes
       - Improper heat range or reach
    • If the spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.

Additional Checks
    • Test the TCC operation.
    • Inspect the exhaust system for possible restriction:
       - Inspect the exhaust system for damaged or collapsed pipes.
       - Inspect the muffler for heat distress or possible internal failure.
       - Test for a plugged 3-way catalytic converter by measuring the exhaust system back pressure. Refer to Restricted Exhaust System Check or Exhaust System Inspection in Engine Exhaust.