| Condition | Actions |
|---|---|
| Abnormalities (server cracking, bumps or missing areas) in the accessory drive belt | Abnormalities in the accessory drive belt and/or components may cause engine RPM variations, noises similar to faulty lower engine and also lead to a misfire condition. A misfire code may be present without an actual misfire condition. Inspect the accessory drive components. Repair or replace all damaged components. |
| Worn, damaged, or misaligned accessory drive components or excessive pulley runout | A misfire code may be present without an actual misfire condition. Inspect the accessory drive components. Repair or replace all damage components. |
| Loose and/or damaged crankshaft pulley | A misfire code may be present without an actual misfire condition. Repair or replace all damaged components. Inspect crankshaft pulley and pulley bolt. |
| Loose torque converter bolts | A misfire code may be present without an actual misfire condition. Inspect torque converter bolts and flywheel. Repair or replace all damaged components. |
| Loose and/or damaged flywheel | A misfire code may be present without an actual misfire condition. Inspect flywheel and flywheel attaching bolts. Repair or replace all damaged components. |
| Excessive piston-to-cylinder bore clearance | Perform cylinder leak down and compression tests. Inspect the piston, piston rings and cylinder bore. Repair or replace all damaged components. |
| Excessive crankshaft thrust bearing clearance | Severely worn thrust surfaces on the crankshaft and/or thrust bearing may permit for and aft movement of the crankshaft and create a misfire code without an actual misfire condition. Inspect the crankshaft end play and crankshaft thrust bearings. Repair or replace all damaged. |
Base Engine Misfire with Abnormal Internal Lower Engine Noises