P0303High urgency
Cylinder 3 Misfire Detected
Powertrain · Ignition
⛔ Avoid highway speeds — risk of catalytic converter damage.
What this means
Cylinder 3 is misfiring. Same root causes as P0302 but specific to cylinder 3.
Likely causes
- Faulty spark plug cylinder 3Most common
- Failed ignition coil cylinder 3Most common
- Bad fuel injector cylinder 3Common
Estimated repair cost
Spark plug replacement$50 – $200
Ignition coil replacement$150 – $350
Compression test + repair$200 – $1,500
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Frequently asked questions
What does P0303 mean?
Cylinder 3 is misfiring. Same root causes as P0302 but specific to cylinder 3.
Is P0303 serious?
Avoid highway speeds — risk of catalytic converter damage.
How much does it cost to fix P0303?
Repair costs for P0303 range from $50 – $200 depending on the root cause and your vehicle.
Can I drive with P0303?
No — this code indicates a serious issue. Stop driving and have the vehicle inspected immediately.