i have a cylinder 6 misfire (P0306). the car was running rough at startup amd regular driving. I have replaced the icm-used, coil-used, spark plug (autolite 605...i think copper cores) and i have the beldin blue wires. I have 5 store brought wires and one used beldin wire due to the original store brought one being melted from the heat from cylinder 6. i also replaced the injector on bank 6 with a used one. Is there anything else i should try or redo?

Also when taken to the dealer they said to change the injector but i told them that i have done that two days earlier and they said cylinder six seems to be sucking in air after there compression test and they said my gas in rich in smell. i just had my upper and lower intake gaskets done also. the misfire was there before the intake job but the sucking was not.