GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 Park Avenue 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 Lack of Power, Sluggishness, or Sponginess

Lack of Power, Sluggish or Spongy

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 in Symptoms .
    • Refer to Visual/Physical Checks in Symptoms .
    • Search for bulletins.

Fuel System Checks
    • Check the system fuel pressure. Refer to Fuel System Pressure Test (VIN K) or Fuel System Pressure Test (VIN 1)
    • Check for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • 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 P0171 Fuel Trim System Lean .
    • 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 P0172 Fuel Trim System Rich .

Sensor/System
    • Using a scan tool, check for excessive spark retard activity. Refer to Knock Sensor (KS) System Description .
    • Check the EGR system for proper operation. Refer to Exhaust Gas Recirculation (EGR) System Description .
    • Check for a restricted air intake system. Refer to Air Intake System Description .

Ignition System
    • Check for proper ignition voltage output using the following steps:
       - Clip the spark tester J 26792 to engine ground.
       - Connect one end of a spark plug wire to the spark tester; leave the other end of the spark plug wire 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; a spark should be observed.
       - Repeat the above steps for each coil.
    • If spark is not present at the coils, check for the following conditions:

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

       - Coils - Cracks, carbon tracking/arcing, or a secondary resistance value outside the specified range.

Coil Resistance
5000 - 8000 ohms (5K - 8K ohms)

       - Spark Plug wires - Signs of arcing/cross firing, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range.

Spark Plug Wire Resistance
1000 to 1500 ohms/per ft.

   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 faulty.

       - Defective module.
       - Ignition System Wiring - Loose ignition module feed or ground connection, or damaged system wiring.
    • Remove spark plugs and check for the following:
       - Fouled plugs
       - Cracks
       - Check the spark plugs for carbon tracking on the porcelain and pitting on the plug wire contact.
       - Improper gap
       - Burned or damaged electrodes
       - Improper heat range or reach
       - Refer to Maintenance Items
    • If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.

Engine Mechanical
    • Excessive oil in combustion chamber-Leaking valve seals. Refer to Oil Leak Diagnosis in Engine Mechanical.
    • Low cylinder compression. Refer to Engine Compression Test in Engine Mechanical.
    • For incorrect basic engine parts. Inspect the following:
       - Camshaft.
       - Cylinder heads.
       - Pistons etc.
    •  Refer to Engine Compression Test in Engine Mechanical.

Additional Checks
    • Check exhaust system for possible restrictions. Check for the following:
    • Inspect exhaust system for damaged or collapsed pipes.
    • Inspect mufflers for heat distress or possible internal failure.
    • For possible plugged Three-Way catalytic converter. Refer to Restricted Exhaust System Check .
    • Check for proper TCC operation. Refer to Diagnostic Starting Point - Automatic Transmission in Automatic Transaxle.