If only one cylinder misfires, the cause is specific to that cylinder — its plug, coil, injector, or compression.

Ignition coils fail from heat cycling, age, and sometimes from running with worn spark plugs that force higher voltage output.

P0303

High Severity

Cylinder 3 Misfire Detected

Ignition System

Cylinder 3 is misfiring.

Common Fix

Replace spark plug or coil

Estimated Cost (DIY)

$5 - $80

Bad spark pluglikely

Faulty coillikely

Bad injectorpossible

Low compressionpossible

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Why only cylinder 3?: If only one cylinder misfires, the cause is specific to that cylinder — its plug, coil, injector, or compression.
How do coils fail?: Ignition coils fail from heat cycling, age, and sometimes from running with worn spark plugs that force higher voltage output.

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