Here are a few possible causes of the P0304 code:
* Faulty spark plug
* Faulty ignition coil
* Dirty fuel injector
* Clogged catalytic converter
* Exhaust leak
* Low compression in cylinder 4
If you are experiencing the P0304 code, it is important to have the problem diagnosed and repaired as soon as possible. A misfire can cause damage to the engine and other components.