Cause | Correction |
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Abnormalities--severe 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 Tensioner Replacement . |
Worn, damaged, or mis-aligned accessory drive components or excessive pulley runout--A misfire code may be present without an actual misfire condition. | Inspect the components, repair or replace as required. |
Loose or improperly 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. |