diagnostic code quetion

P0304 Cylinder 4 Misfire DetectedPossible Causes Setting Conditions ASD relay output circuit to the ignition coil or injector has high resistance Base engine mechanical problem that affects only one cylinder Check for air leaks in the Air Induction system (e.g., in the intake manifold) Check for air leaks in the EGR system and in its related hoses and/or valve Check for air leaks in the PCV system and in its related hoses and/or valve Coil control circuit problem that affects only one cylinder Fuel component (i.e., dirty injector, fuel filter clogged, low fuel pressure) Ignition system problem (coil, spark plug or boot) that affects one cylinder Injector control circuit that affects only one cylinder Engine running; Target Learning Coefficient updated, and the PCM detected a misfire rate of 1.5% (High Emissions 2T), or a misfire rate of 10-30% (Catalyst Damaging 1T) in Cylinder 4 during testing. If the misfire is severe, the MIL will flash on/off on the 1st trip! This code sets in 2 Trip(s). This code will turn on the MIL (Malfunction Indicator Lamp)