how do i fix a obd 2 code of po304 i changed the coil pack plugs and wires on 2007 Dodge Caravan

and the code does not clear

Asked by for the 2007 Dodge Caravan
What do you mean 'the code does not clear'? It will not go off by itself, it has to be cleared with a scanner or possibly disconnecting the battery. Is misfire gone after replacing parts?