For 1990-2009 cars

Checks | Action
--- | ---
DEFINITION: A mild to severe ping which usually occurs worse while under acceleration. The engine makes sharp metallic knocks that change with throttle opening.
Preliminary Checks |

• | Refer to Important Preliminary Checks Before Starting in Symptoms - Engine Controls .

• | Search for bulletins.

• | Inspect the engine control module (ECM) grounds for being clean, tight, and in their proper locations. Refer to Engine Controls Schematics .

• | If the scan tool readings are normal and there are not any engine mechanical faults, fill the fuel tank with a known high quality fuel that meets the vehicle's minimum octane requirements. Refer to Fuel System Specifications . Test the vehicle and re-evaluate the vehicle's performance.

Fuel System |

• | Inspect the fuel system. Refer to Fuel System Diagnosis .

• | Test for incorrect fuel pressure.

• | Test for a restricted fuel filter.

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

• | Inspect the MAF sensor for proper operation or intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

• | Inspect the ECT sensor for proper operation or intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

• | Test for a restricted or plugged fuel injector. Refer to Fuel Injector Balance Test with Special Tool .

• | Test the items that can cause an engine to run lean (long term fuel trim near 23 percent). For a lean condition, refer to DTC P0171 or P0174 .

Ignition System | Ensure that the spark plugs are the correct heat range.
Engine Cooling System | Test for an overheating condition. Refer to Engine Overheating in Engine Cooling.
Engine Mechanical | Inspect for the following engine mechanical problems:

• | Excessive oil in combustion chamber/leaking valve seals--Refer to Oil Consumption Diagnosis in Engine Mechanical-3.0L (L81).

• | High cylinder compression--Refer to Engine Compression Test in Engine Mechanical-3.0L (L81).

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

• | Check for incorrect camshaft timing. Refer to Timing Belt Timing Adjustment in Engine Mechanical-3.0L (L81).

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

- | Camshafts--Refer to Camshaft and Bearings Cleaning and Inspection in Engine Mechanical-3.0L (L81).

- | Cylinder heads--Refer to Cylinder Head Cleaning and Inspection in Engine Mechanical-3.0L (L81).

- | Pistons, connecting rods or bearings--Refer to Piston, Connecting Rod, and Bearing Cleaning and Inspection in Engine Mechanical-3.0L (L81).

Additional Checks |

• | Test the park/neutral position (PNP) switch operation. Refer to DTC P0705 or DTC P0706 .

• | Test the transmission torque converter clutch (TCC) for proper operation. Applying the TCC too soon can cause the engine to spark knock. Refer to Torque Converter Diagnosis in Automatic Transmission-4L30-E.