P0303 Cylinder 3 Misfire Detected
What does P0303 mean?
P0303 — Cylinder 3 Misfire Detected. This is an OBD-II diagnostic trouble code a scanner retrieves when your vehicle's computer detects cylinder 3 misfire detected. The level of risk depends on how the vehicle is currently running and how long you've been driving with the light on.
Common causes of P0303
- Faulty spark plug or ignition coil on cylinder 3
- Clogged fuel injector on cylinder 3
- Vacuum leak at cylinder 3 intake runner
- Low compression in cylinder 3
- Valvetrain or timing issues
How to fix P0303
- Check the misfire counter for cylinder 3 on an OBD-II scanner
- Swap the coil and spark plug and see if the misfire follows
- Test injector operation for cylinder 3
- Compression test cylinder 3
- Inspect the intake manifold gasket near cylinder 3