For 1990-2009 cars

Inspection/Tests | Action
--- | ---
DEFINITION: Engine delivers less than expected power. Little or no increase in speed when the accelerator pedal is pushed down part way.
Preliminary Inspections |

• | Refer to Important Preliminary Inspections Before Beginning in Symptoms - Engine Controls .

• | Search for bulletins.

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

• | Remove the air filter element and inspect for dirt or for restrictions. Refer to Air Cleaner Element Replacement and replace as necessary.

Fuel System |

• | Test for incorrect fuel pressure. Refer to Fuel System Diagnosis .

• | Inspect for a restricted fuel filter. Refer to Fuel System Diagnosis .

• | Inspect for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

• | Test the fuel injectors. Refer to Fuel Injector Diagnosis .

• | Inspect for the following that may cause the engine to run rich:

Notice: Refer to Heated Oxygen and Oxygen Sensor Notice in the Preface section.

- | Water intrusion in the heated oxygen sensor (HO2S) connector

- | Purging of a saturated evaporative emission (EVAP) canister

- | Incorrect fuel pressure--Refer to Fuel System Diagnosis .

- | A leaking fuel pressure regulator--Refer to Fuel System Diagnosis .

- | Leaking fuel injectors--Refer to Fuel System Diagnosis .

- | Vacuum hoses that are split, kinked, or improperly connected

- | An air intake duct that is collapsed or restricted--Refer Air Cleaner Outlet Duct Replacement .

- | An air filter that is dirty or restricted--Refer to Air Cleaner Element Replacement .

• | Inspect for the following conditions that may cause the engine to run lean:

Notice: Refer to Heated Oxygen and Oxygen Sensor Notice in the Preface section.

- | Water intrusion in the HO2S connector

- | An exhaust leak between the HO2S and the engine--Refer to Exhaust Leakage .

- | Vacuum leaks

- | Incorrect fuel pressure--Refer to Fuel System Diagnosis .

- | Restricted fuel injectors--Refer to Fuel Injector Diagnosis .

- | Fuel contamination--Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

- | Vacuum hoses that are split, kinked, or improperly connected

Sensor/System | Monitor the knock sensor (KS) system for excessive spark retard activity with a scan tool. Refer to Scan Tool Data List .
Ignition System | In order to properly inspect the spark plugs or to correct a condition, refer to the following procedures:

• | Ignition System Specifications

• | Spark Plug Replacement

• | Spark Plug Inspection

• | Inspect for proper secondary ignition voltage output with J 26792 HEI Spark Tester.

• | An improper spark plug gap will cause a driveability condition. Gap the spark plugs using a wire gage gap tool.

• | If the spark lugs are found to be fouled, determine the cause before replacing the spark plugs.

• | Inspect for damaged or misaligned spark plug boots.

• | Monitor the Misfire Current Counters while driving the vehicle in the conditions that the symptom occurred. If a misfiring cylinder can be located, use the DTC P0300 table for diagnosis. Refer to DTC P0300 .

Engine Mechanical |

• | Inspect for incorrect camshaft timing.

• | Inspect for excessive oil in the combustion chambers and leaking valve seals. Refer to Oil Consumption Diagnosis .

• | Proper camshaft actuator system operation--Refer to Camshaft Actuator System Description .

• | Test the cylinder compression. Refer to Engine Compression Test .

• | Inspect for incorrect, worn, or damaged basic engine parts, including the following:

- | The camshaft--Refer to Camshafts Cleaning and Inspection .

- | The cylinder head--Refer to Cylinder Head Cleaning and Inspection .

- | The pistons, etc.--Refer to Piston, Connecting Rod, and Bearing Cleaning and Inspection .

Additional Inspections |

• | Inspect the exhaust system for possible restrictions. Refer to Restricted Exhaust .

• | Inspect the exhaust system for damaged or collapsed pipes.

• | Inspect the mufflers for heat distress or internal failure.

• | Inspect the transmission torque converter clutch (TCC) for proper operation. Refer to Symptoms - Automatic Transmission .