For 1990-2009 cars

#### Lack of Power, Sluggish or Spongy

Checks | Action
--- | ---
DEFINITION: The engine delivers less than the expected power. When the accelerator pedal is pushed part-way down, there is little or no increase in the speed.
Preliminary Checks |

• | Refer to Diagnostic System Check - Engine Controls .

• | Refer to Symptoms - Engine Controls .

• | Search for the service bulletins.

• | Check and compare the customer's vehicle to a similar vehicle. Ensure that the customer's vehicle has an actual problem.

• | Check the air cleaner filter for dirt or for restrictions.

Fuel System Checks |

• | Check the fuel system pressure. Refer to Fuel System Diagnosis .

• | Check the fuel injectors. Refer to Fuel Injector Balance Test with Special Tool or Fuel Injector Balance Test with Tech 2 .

• | Check for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

• | Check items which can cause an engine to run rich, where the long term fuel trim is significantly in the negative range. Refer to Diagnostic Aids for DTC P0172 .

• | Check for conditions that can cause an engine to run lean, where the long term fuel trim is significantly in the positive range. Refer to Diagnostic Aids for DTC P0171 .

• | Check the throttle linkage and the throttle cables in order to ensure that the throttle plate opens fully.

Sensor/System |

• | Use a scan tool in order to monitor the knock sensor (KS) system for excessive spark retard activity.

• | Check for proper operation of the manifold absolute pressure (MAP) sensor. Refer to DTC P0105 .

• | Check for proper operation of the throttle position (TP) sensor. Refer to DTC P0105 .

• | Check for proper operation of the oxygen sensor 1 (O2S) 1.

• | Check for a restricted air intake system.

Ignition System |

• | Check for proper ignition voltage output with the J 36012-A Ignition System Diagnostic Harness and with a J 26792 Spark Tester or equivalent.

• | Check the spark plugs for the following conditions:

- | Wet or fuel fouled spark plugs

- | Cracks on the spark plugs

- | Wear

- | Improper spark plug gap

- | Burned electrodes or heavy deposits

- | Heavy deposits

• | If the spark plugs are fuel or oil-fouled, determine the cause of the fouling before you replace the spark plugs.

• | Check the ignition control module (ICM) for proper ground connection.

• | Check the ignition coils for cracks or for carbon tracking.

Engine Mechanical | Check the engine for the following engine mechanical problems:

• | Low compression--Refer to Engine Compression Test in Engine Mechanical 2.2 L (L61).

• | Correct valve timing--Refer Symptoms - Engine Mechanical in Engine Mechanical 2.2 L (L61).

• | Check for leaking cylinder head gasket. Refer to Engine Compression Test in Engine Mechanical 2.2 L (L61).

• | Check for a worn camshaft, or for an incorrect camshaft. Refer to Symptoms - Engine Mechanical in Engine Mechanical 2.2 L (L61).

Additional Checks |

• | Check for proper operation of the transaxle and the torque converter clutch (TCC). Refer to Road Test in Automatic Transmission 4T40-E/4T45-E.

• | Check the exhaust system for a possible restriction:

- | Inspect the exhaust system for damaged or for possible collapsed pipes.

- | Inspect the muffler for heat distress or for possible internal failure.

- | Check for possible plugged three-way catalytic converter. Refer to Restricted Exhaust in Engine Exhaust.

• | Check the vacuum lines for kinks or leaks.

• | Check the generator output voltage. Refer to Diagnostic System Check - Engine Electrical in Engine Electrical.

• | Check the A/C system operation. Refer to Symptoms - HVAC Systems - Manual in HVAC Systems.

• | If all procedures have been completed and no malfunctions have not been found, review and inspect the following items:

- | Visually and physically inspect all electrical connections within the suspected circuit and/or systems.

- | Check scan tool data. Refer to Scan Tool Data List .