P0304 Cylinder 4 Misfire Detected
What does P0304 mean?
P0304 — Cylinder 4 Misfire Detected. This is an OBD-II diagnostic trouble code a scanner retrieves when your vehicle's computer detects cylinder 4 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 P0304
- Faulty spark plug or ignition coil on cylinder 4
- Clogged or leaking injector on cylinder 4
- Vacuum leak at the cylinder 4 intake runner
- Low compression in cylinder 4
- Engine mechanical wear
How to fix P0304
- Confirm cylinder 4 misfire counts with an OBD-II scanner
- Swap the ignition coil and spark plug to test if the fault follows
- Verify the fuel injector on cylinder 4
- Compression test cylinder 4
- Inspect for intake leaks at that runner