troble code po300 repair

Troble code po300 is multi misfire.What do I do to repair.

THE troble code po300 is multimisfire. I would like to know where to start to repair.

Check the plugs. Was my cause of misfires 80 percent of time.

Yes it is a general misfire code...clean or replace plugs...replace wires if in excess of 60k miles... on the ignition.. remove the four bolts( 5/32) and remove the assembly... remember where the ignition wires go back on by labeling them... while assembly is removed use a light sandpaper on the bottom of the assembly and where it attaches to the transmission housing. Use dielectrical grease sparingly on the outer perimeter bottom of the assembly to reduce moisture. The ground contact necessary is inherent with good clean bolts.

Clean the coils with the sandpaper to ensure good wire contact. That should rid your P300 code. If you are reusing the wires, put dielectric grease just inside the spark plug wire boot to ensure sealing and pliability.

Just to add another possible cause, if plug 1 happens to be covered in oil (may cause misfires as well), time for a new valve cover gasket along with plugs.