P0303
Cylinder 3 Misfire Detected
Your engine's computer has detected that cylinder number 3 is not firing correctly, meaning it's not contributing power as it should.
The powertrain control module (PCM) has detected a misfire condition in cylinder number 3.
Common causes
- high
Faulty Spark Plug (Cylinder 3)
A worn, fouled, or damaged spark plug in cylinder 3 is a very common cause of a single-cylinder misfire.
Typical part cost: $10-30
- high
Faulty Ignition Coil or Wire (Cylinder 3)
A failing ignition coil or damaged spark plug wire specific to cylinder 3 will prevent proper spark delivery.
Typical part cost: $50-200
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First things to check
- 1Swap spark plug from cylinder 3 to another cylinder and see if the misfire moves.
- 2Swap ignition coil from cylinder 3 to another cylinder and see if the misfire moves.
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Related codes
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Frequently asked questions
How serious is a P0303 code?
It's serious enough to warrant immediate attention. While a single misfire might not immediately strand you, it can cause significant engine damage over time, especially to the catalytic converter, if not addressed.
Can a P0303 code be caused by a bad fuel pump?
While a bad fuel pump typically causes misfires across multiple cylinders (P0300) due to overall low fuel pressure, it's less likely to cause a P0303 specifically unless there's an additional issue like a clogged fuel filter affecting only that cylinder's fuel delivery.
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