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P0303: Cylinder 3 Misfire Detected
Cylinder number 3 is misfiring.
High Severity
$50 – $500
Can I Keep Driving with Code P0303?
Avoid extended driving.
What P0303 Means
Cylinder 3 specific misfire. Same playbook as P0301 and P0302: spark, fuel, or compression.
Common Causes
- Bad spark plug in cylinder 3 — see repair cost
- Failed ignition coil on cylinder 3
- Clogged fuel injector — see repair cost
- Low cylinder compression
Diagnostic Tips
- Coil swap test is the quickest way to isolate.
- Spark plugs are cheap, do all of them if they are old.
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Get My Free EstimateFrequently Asked Questions
Can a misfire ruin my engine?
Not directly. But unburned fuel reaches the cat and can destroy it.