For 1990-2009 cars

#### 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 Powertrain On Board Diagnostic (OBD) System Check .

• | Refer to Symptoms .

• | Search for service bulletins.

• | Check and compare the customers vehicle to a similar vehicle. Make sure the customers vehicle has an actual problem.

• | Check the air cleaner filter for dirt or being plugged.

Fuel System Checks |

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

• | Check the fuel injectors. Refer to Fuel Injector Balance Test .

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

• | Check items which can cause an engine to run rich (long term fuel trim is significantly in the negative range). Refer to DTC P0172 Fuel Trim System Rich .

• | Check items that can cause an engine to run lean (long term fuel trim is significantly in the positive range). Refer to DTC P0171 Fuel Trim System Lean .

Sensor/System |

• | Using a scan tool, monitor KS system for excessive spark retard activity.

• | Check for proper operation of the MAP sensor.

• | Check for proper operation of the TP sensor.

• | Check the EGR system for proper operation.

• | Check for a restricted air intake system.

Ignition System |

• | Check for proper ignition voltage output with the spark plug jumper wires J 36012-A and spark tester J 26792 .

• | 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

• | If the spark plugs are fuel or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.

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

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

Engine Mechanical |

• | Check the engine for the following engine mechanical problems:

- | Check for low compression.

- | Check for correct valve timing.

- | Check for leaking cylinder head gasket.

- | Check for a worn or a incorrect camshaft.

• | Refer to Base Engine Misfire Diagnosis in Engine Mechanical.

Additional Checks |

• | Check for proper operation of the TCC. Refer to Torque Converter Clutch Pulse Width Modulation Solenoid Circuit Electrical Check in Automatic Transaxle.

• | 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 System Check .

• | Check the vacuum lines for kinks or leaks.

• | Check the generator output voltage. Repair the generator if the output voltage is less than 11 volts or more than 16 volts.

• | Check the A/C system operation. The A/C clutch should cut out at the wide open throttle (WOT) position.

• | 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.