GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2001 🢒 Catera 🢒 Engine 🢒 Engine Controls - 3.0L (L81) 🢒 Lack of Power, Sluggishness, or Sponginess

Checks

Action

DEFINITION: The engine delivers less than expected power. Little increase in speed, or a total lack of acceleration when the accelerator pedal is pushed down part way.

Preliminary Inspections
    • Refer to Important Preliminary Inspections Before Starting in Symptoms - Engine Controls .
    • Search for bulletins.
    • Inspect the engine control module (ECM) grounds for being clean, tight and in the proper locations. Refer to Engine Controls Schematics .
    • Remove the air filter element and inspect for dirt or for being restricted.
    • Inspect the intake air ducts for the following conditions:
       - Restrictions
       - Improperly installed hoses
       - Leaks
       - Collapsed hoses

Fuel System
    • Inspect the fuel system. Refer to Fuel System Diagnosis .
    • Test for incorrect fuel pressure.
    • Test for a restricted fuel filter.
    • Test for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Inspect the items which can cause an engine to run rich (long term fuel trim near -13 percent). For a rich condition, refer to DTC P0172 or P0175 .
    • Inspect the items that can cause an engine to run lean (long term fuel trim near 23 percent). For a lean condition, refer to DTC P0171 or P0174 .

Sensor/System
    • Use a scan tool in order to monitor the knock sensor (KS) system for excessive spark retard activity. Refer to Detonation/Spark Knock .
    • Check for proper operation of the throttle control system components. Use the scan tool special functions to actuate the system. Verify that the throttle opens to 100 percent. With a scan tool, monitor the following throttle control system components:
       - Throttle position (TP) sensors
       - Accelerator pedal position (APP) sensors
       - Throttle actuator

Ignition System
    • Test for proper ignition voltage output with a J 26792 Spark Tester . Refer to Electronic Ignition (EI) System Diagnosis .
    • Test for secondary ignition leakage. Refer to the procedure in the Diagnostic Aids portion of Electronic Ignition (EI) System Diagnosis .
    • Remove the spark plugs and inspect for the following conditions:
       - Correct heat range
       - Wet plugs
       - Cracks
       - Wear
       - Improper gap
       - Burned electrodes
       - Heavy deposits
    • An improper spark plug gap will cause a driveability concern. Gap the spark plugs using a wire gauge gap tool. Refer to Spark Plug Replacement .
    • Determine the cause of the fouling before replacing the spark plugs if the spark plugs are gas, coolant or oil fouled. Refer to Spark Plug Inspection . Once you determine the cause of the fouling, refer to one of the following procedures:
       - For diagnosis of a rich condition, refer to DTC P0172 or P0175 .
       - For diagnosis of coolant contaminated spark plugs, refer to Loss of Coolant in Engine Cooling.
       - For diagnosis of oil fouled spark plugs, refer to Oil Consumption Diagnosis in Engine Mechanical-3.0 (L81).

Engine Mechanical
    • Excess oil in combustion chamber due to leaking valve seals--Refer to Oil Consumption Diagnosis in Engine Mechanical-3.0L (L81).
    • Check for incorrect camshaft timing. Refer to Timing Belt Timing Adjustment in Engine Mechanical-3.0L (L81).
    • Inspect the following components for incorrect basic engine parts:
       - Camshafts--Refer to Camshaft and Bearings Cleaning and Inspection in Engine Mechanical-3.0L (L81).
       - Cylinder heads--Refer to Cylinder Head Cleaning and Inspection in Engine Mechanical-3.0L (L81).
       - Pistons, connecting rods or bearings--Refer to Piston, Connecting Rod, and Bearing Cleaning and Inspection in Engine Mechanical-3.0L (L81).

Additional Inspections
    • Inspect the following components of the exhaust system for possible restrictions:
       - The exhaust system for physical damage
       - The mufflers for heat distress or possible internal failure
       - The catalytic converters for possible plugged pipes by comparing the exhaust system back pressure on each side of engine--Refer to Restricted Exhaust in Engine Exhaust.
    • Test for proper operation of the intake resonance switchover valve and the intake plenum switchover valve. Refer to Intake Manifold Runner Control System Diagnosis .
    • Test the transmission torque converter clutch (TCC) for proper operation. Refer to Torque Converter Diagnosis in Automatic Transmission-4L30-E.
    • Check for other transmission related faults that might cause the transmission to operate in a default mode. Refer to Diagnostic System Check - Automatic Transmission Shift Lock Control in Automatic Transmission-4L30-E.