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 and lead to a misfire DTC. A misfire code may be present without an actual misfire condition. | Replace the drive belt. Refer to Drive Belt Replacement . | ||||
Worn, damaged, or mis-aligned accessory drive components or excessive pulley runout - May lead to a misfire DTC. A misfire code may be present without an actual misfire condition. | Inspect the components and 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 . | ||||
Restricted exhaust system A severe restriction in the exhaust flow can cause significant loss of engine performance and may set a DTC. Possible causes of restrictions include collapsed or dented pipes or plugged mufflers and/or catalytic converters. | Repair or replace, as required. | ||||
Improperly installed or damaged vacuum hoses | Repair or replace, as required. | ||||
Improper operation of the intake rocker arm control system |
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Improper sealing between the intake manifold, fuel injection manifolds, cylinder heads and throttle body | Replace components, as required. | ||||
Improperly installed or damaged MAP sensor and/or seal The O-ring seal of the MAP sensor should not be torn or damaged. | Repair or replace the MAP sensor, as required. | ||||
Improperly installed or damaged EVAP purge solenoid and/or hoses | Repair or replace the EVAP purge solenoid, as required. | ||||
Worn or incorrectly adjusted rocker arms | Adjust or replace rocker arms, as required. | ||||
Stuck valves Carbon buildup on the valve stem can cause the valve not to close properly. | Repair or replace, as required. | ||||
Excessively worn or mis-aligned camshaft timing components | Replace the components, as required. | ||||
Worn camshaft lobes | Replace the camshaft, as required. | ||||
Faulty cylinder head gaskets and/or cracking or other damage to the cylinder heads and engine block cooling system passages Refer to Diagnostic Starting Point - Engine Cooling . Coolant consumption may or may not cause the engine to overheat. |
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Worn piston rings Oil consumption may or may not cause the engine to misfire. |
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Damaged crankshaft sprocket reluctor teeth Damaged crankshaft sprocket reluctor teeth can result in different symptoms depending on the severity and location of the damage.
| Replace or repair, as required. |