hello i have a 03 busa with a rebuilt motor having problems the bike fells like its not smooth and hesitating dose not sound like its missing i checked the plugs and the #4 plug is black 1 2 3 look good i did notice the mass air sensor on back of the air box looks like it was broken and glued back together i also had the injectors and air cleaner cleaned i'am running a full muzzy header w/ power commander