What is the next step?

Question

I have replaced all 6 plugs, 1 coil pack, and all necessary gaskets. Compression is 120. I added Sea Foam to clean the fuel injectors. It runs perfect. No symptoms of misfire.

Answer 1

P0304 Misfire number 4 cylinder

 Check the fuel injector connection , not properly secured will set a random misfire just from one fuel injector not properly secured, and this also goes for the ignition coil .