Cause
|
Correction
|
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.
|
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 crankshaft balancer
A misfire code may be present without an actual misfire
condition.
|
Repair or replace the flywheel and/or balancer as required.
|
Loose torque converter bolts
A misfire code may be present without an actual misfire
condition.
|
Inspect the torque converter bolts and flywheel and repair or
replace as required.
|
Loose or improperly installed engine flywheel
A misfire code may be present without an actual misfire
condition.
|
Repair or replace the flywheel and/or balancer as required.
|
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.
|
Air in fuel system
|
Inspect fuel filter, fuel system for leaks and/or restrictions and
repair or replace as required.
|
Bent and/or worn valve pushrod
|
Inspect valve pushrod and valve rocker arm and repair or replace
as required.
|
Worn or loose rocker arms
The rocker arm bearing end caps and/or needle bearings should be
intact and in the proper position.
|
Replace the valve rocker arms as required.
|
Improperly installed or damaged vacuum hoses
|
Repair or replace as required.
|
Improper sealing between the intake manifold and cylinder heads or
throttle body.
|
Replace the intake manifold, gaskets, cylinder heads, and/or
throttle body as required.
|
Sticking valve
Carbon buildup on the valve stem can cause the valve not to close
properly.
|
Repair or replace as required.
|
Excessively worn or mis-aligned timing belt
|
Replace the timing belt and sprockets as required.
|
Damaged or misaligned timing gears
|
Inspect timing gears and replace as required.
|
Worn or faulty camshaft lobes
|
Replace the camshaft and valve lash adjusters.
|
Excessive oil pressure
A lubrication system with excessive oil pressure may lead to
excessive valve lifter pump up and loss of compression.
|
| • |
Repair or replace the oil pump as required. |
|
Faulty cylinder head gasket and/or cracking or other damage to the
cylinder head and engine block cooling system passages
Coolant consumption may or may not cause the engine to
overheat.
|
| • |
Inspect the cylinder head, engine block, and/or
head gasket. |
| • |
Repair or replace as required. |
|
Worn piston rings
Oil consumption may or may not cause the engine to misfire.
|
| • |
Perform cylinder leak down and compression testing
to identify the cause. |
| • |
Repair or replace as required. |
|
Overfilled Crankcase
|
| • |
Check engine oil level with vehicle on a level
surface. |
| • |
Correct any overfilled condition. |
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