Don’t really know where so start. Checked all fittings starts up and runs smooth at idle. I believe that I am running on 5 cylinders at WOT. Motor still seem smooth not like it is missing. Again new to boat motors but mechanically inclined. Didn’t think it would be fuel pump because I can run steady at 3800 rpm all day without issue. How do I go about testing pulse fitting?? Not really sure what that is but will research.