For 1990-2009 cars

#### Lack Of Power, Sluggishness, Or Sponginess

Checks | Action
--- | ---
DEFINITION: The engine delivers less than expected power. There is little or no increase in speed when partially applying the accelerator pedal.
Preliminary Checks |

• | Refer to Diagnostic System Check - Engine Controls .

• | Refer to Symptoms - Engine Controls .

• | Compare the customers vehicle with a similar unit in order to determine if the customer has an actual problem.

• | Remove the air filter element and check for dirt or restrictions.

• | Check the air inlet duct for any blockage or restrictions.

• | Check the transmission shift pattern and down-shift operation.

Sensor/System | Inspect the mass air flow (MAF) sensor operation. Run the engine to normal operating temperature. Turn OFF all accessories and observe the MAF sensor at idle with a scan tool. If the MAF sensor reading is more than 3.5 g/s refer to DTC P0101 .
Fuel System Checks |

• | Check for a restricted fuel filter or incorrect fuel pressure.

• | Check the fuel injectors. Perform the following procedures:

- | The Fuel Injector Coil Test--Refer to Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Between 10-35 Degrees C (50-95 Degrees F) or to Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Outside 10-35 Degrees C (50-95 Degrees F) .

- | The Fuel Injector Balance Test--Refer to Fuel Injector Balance Test with Special Tool .

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

Ignition System Checks |

• | Check for the proper ignition voltage output with a J 26792 Spark Tester.

• | Inspect the spark plugs for correct operation and good ignition system performance. Refer to Spark Plug Inspection .

• | Check the knock sensor (KS) and the sensors circuit shielding. The knock sensor is not diagnosed for excessive activity. A faulty knock sensor or signal interference could cause excessive retard of the ignition timing advance. Observe the spark parameter on a scan tool and compare with a known good vehicle. A typical value with the transmission in OD at 105 km/h (65 mph) is 26-32 degrees.

Exhaust System Checks |

• | Check the exhaust system for a possible restriction. Refer to Restricted Exhaust in Engine Exhaust.

• | Inspect the exhaust system for damaged or collapsed pipes. Inspect the muffler for heat distress or a possible internal failure.

Engine Mechanical Check |

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

- | A low compression

- | An incorrect valve timing

- | An incorrect or worn camshaft

• | Refer to Diagnostic Starting Point - Engine Mechanical in Engine Mechanical-1.8L.

Additional Checks |

• | Check the powertrain control module (PCM) grounds for being clean, tight, and in the proper locations. Refer to Engine Controls Schematics .

• | Check the generator output voltage.