For 1990-2009 cars

Cause | Correction
--- | ---
Low oil pressure. | Perform an oil pressure test. Refer to Oil Pressure Diagnosis and Testing .
Detonation or spark knock. | Verify the correct operation of the ignition controls system. Refer to Diagnostic Starting Point - Engine Controls .
Loose torque converter bolts. |

1. Inspect the torque converter bolts and flex plate. Refer to Flex Plate/Torque Converter Vibration Test for 5L40-E/5L50-E.

or

Refer to Flex Plate/Torque Converter Vibration Test for 6L50/6L80/6L90.

2. Repair or replace, as required. Refer to Torque Converter Replacement for 5L40-E/5L50-E.

or

Refer to Torque Converter Replacement for 6L50/6L80/6L90.

or

Refer to Engine Flywheel Replacement .

Cracked flywheel - automatic transmission. | Repair or replace the flywheel. Refer to Engine Flywheel Replacement .
Above acceptable connecting rod bearing clearance. | Inspect the following components and repair, as required:

• | The connecting rod bearings

• | The connecting rods

• | The crankshaft

Refer to Piston, Connecting Rod, and Bearing Removal .

Above acceptable crankshaft bearing clearance. | Inspect the following components and repair, as required:

• | The crankshaft bearings

• | The crankshaft journals

• | The cylinder block crankshaft bearing bore

Refer to Piston, Connecting Rod, and Bearing Removal .