For 1990-2009 cars

Inspection/Tests | Action
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DEFINITION: A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that changes with throttle opening.
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 and Engine Controls Schematics .

• | If there are no engine mechanical faults, fill the fuel tank with a known high quality fuel that meets the vehicles minimum octane requirements. Road test the vehicle and re-evaluate the vehicles performance.

Fuel System |

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

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

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

Sensor/System |

• | 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 heated oxygen sensor (HO2S) connector

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

- | Any vacuum leaks

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

- | Any restricted fuel injectors--Refer to Fuel Injector Diagnosis .

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

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

• | Inspect for an engine coolant temperature (ECT) sensor that has shifted in value . Refer to Temperature Versus Resistance .

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 system output. Refer to Electronic Ignition (EI) System Diagnosis .

• | 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.

Engine Cooling System | Inspect for obvious overheating conditions:

• | Low engine coolant--Refer to Loss of Coolant .

• | A faulty thermostat--Refer to Thermostat Diagnosis .

• | A restricted air flow to the radiator or restricted coolant flow through the radiator

• | An inoperative electric cooling fan--Refer to Cooling Fan Inoperative .

• | Proper tension on the drive belts

• | Correct coolant solution should be a 50/50 mix. Refer to Cooling System Description and Operation .

Engine Mechanical | Inspect for the following engine mechanical conditions:

• | Excessive oil in combustion chamber or leaking valve seals--Refer to Oil Consumption Diagnosis .

• | High cylinder compression--Refer to Engine Compression Test .

• | Combustion chambers for excessive carbon buildup--Clean the combustion chamber by using top engine cleaner. Follow the instructions on the can.

• | Incorrect camshaft timing

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

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

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

- | The pistons, etc.--Refer to Cylinder Head Cleaning and Inspection .

• | Refer to Symptoms - Engine Mechanical .