Cause | Correction | ||||||||
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Abnormalities, such as extreme cracking, bumps or missing areas in the accessory drive belt. Abnormalities in the accessory drive system and/or components may cause engine RPM variations, noises similar to a faulty lower engine and also lead to a misfire condition. A misfire code may be present without an actual misfire condition. | Replace the drive belt. Refer to Drive Belt Replacement - Accessory. | ||||||||
Worn, damaged, or mis-aligned accessory drive components or above acceptable pulley runout. A misfire code may be present without an actual misfire condition. | Inspect the components and repair or replace, as required. | ||||||||
Loose or incorrectly installed engine flywheel or crankshaft balancer. A misfire code may be present without an actual misfire condition. | Repair or replace the flywheel and/or balancer, as required. Refer to Engine Flywheel Replacement or Crankshaft Balancer Replacement. | ||||||||
Worn piston rings. Oil consumption may or may not cause the engine to misfire. |
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Worn crankshaft thrust bearings. Severely worn thrust surfaces on the crankshaft and/or thrust bearing may permit fore and aft movement of the crankshaft and create a DTC without an actual misfire condition. | Replace the crankshaft and bearings, as required. Refer to Crankshaft and Bearing Removal. |