For 1990-2009 cars

#### Lack of Power, Sluggish or Spongy

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 Starting 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 in Wiring Systems 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 Balance Test with Special Tool , Fuel Injector Balance Test with Tech 2 , or Fuel Injector Solenoid Coil Test .

Sensor/System |

• | 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.

- | Any water intrusion in the HO2S connector

- | The engine oil contaminated by fuel

- | An EVAP canister purge condition

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

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

- | A leaking fuel injectors--Refer to Fuel System Diagnosis .

- | Any vacuum hoses that are split, kinked, or improperly connected

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

- | Any water intrusion in the HO2S connector

- | An exhaust leak between the HO2S and the engine--Refer to Restricted Exhaust in Engine Exhaust.

- | Any vacuum leaks

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

- | Any restricted fuel injectors--Refer to Fuel Injector Balance Test with Tech 2 .

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

- | Any vacuum hoses that are split, kinked, or improperly connected

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

- | Spark Plug Replacement

• | Remove spark plugs and inspect for the following conditions:

- | Correct heat range

- | Wet plugs

- | Cracks

- | Wear

- | Improper gap

- | Burned electrodes

- | Heavy deposits

- | Verify that the spark plugs are of the correct type.

• | Inspect for proper ignition voltage output with the J 26792 (SA9199Z) Spark Tester.

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

• | Determine the cause of the fouling before replacing the spark plugs.

• | Inspect for damaged or misaligned spark plug boots.

• | Inspect the electronic ignition (EI ) module for proper ground connection.

• | 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 in Engine Mechanical.

• | Test for low cylinder compression. Refer to Engine Compression Test in Engine Mechanical.

• | Inspect for incorrect basic engine parts, including the following components:

- | The camshaft--Refer to Camshaft Cleaning and Inspection in Engine Mechanical.

- | The cylinder heads--Refer to Cylinder Head Cleaning and Inspection in Engine Mechanical.

- | The pistons, etc.--Refer to Piston, Connecting Rod, and Bearing Installation in Engine Mechanical.

Additional Inspections |

• | Inspect the exhaust system for the following possible restrictions:

- | The exhaust system for damaged or collapsed pipes

- | The mufflers for heat distress or internal failure

- | Refer to Restricted Exhaust in Engine Exhaust

• | Inspect the transmission torque converter clutch (TCC) for proper operation. Refer to Torque Converter Diagnosis in Automatic Transaxle 4T40-E/ 4T45-E.