OBD2 Automotive Error Code P0304: How to Fix It

Q: What causes a P0304 cylinder 4 misfire code?

Common causes include worn spark plugs, faulty ignition coils, clogged fuel injectors, vacuum leaks, low compression due to worn rings or valves, or timing chain/belt issues.

Q: Can I drive with a P0304 code?

While you may be able to drive short distances, continuing to drive with a misfire can damage the catalytic converter and cause more expensive repairs. Address the issue promptly.

Q: How much does it cost to fix a P0304 misfire?

Costs vary widely depending on the cause. Simple fixes like spark plugs cost $100-200, while ignition coils run $150-400. More serious issues like low compression can cost $1,500-3,000 or more.

Q: Will a P0304 code clear itself?

The code may temporarily clear if the misfire condition improves, but it will likely return if the underlying problem isn't fixed. It's best to diagnose and repair the root cause.

Abstract

The P0304 error code indicates a misfire detected in cylinder 4 of your engine, meaning the fuel and air mixture in that cylinder isn't burning properly. This can cause rough idling, reduced power, poor fuel economy, and potential engine damage if left unaddressed.