 2002 yamaha f225 misfire
last summer engine started w/ a cold running slight misfire so we just idled a little longer each run before getting up on plane.this summer got to be more problematic.As i open the throttle the engine misfires a little at maybe 1800 rpms so i back out maybe 200-300 rpms,run there a minute,add more throttle til it misses,back off a little.takes maybe 4-5 steps til I can get on plane at 4000 rpm.Once up and running it's fine for the rest of the trip.When it was real bad a month ago, it would miss at cold idle so i pulled one plug wire at a time to try to isolate it to one cylinder.Each wire made the engine run much worse so it's not just a one cylinder problem.Also could hear what sounded like engine popping back in the intake which makes me think it's lean.replaced plugs and ran the engine on injector cleaner we use at the dealer where i work as a master car tech.had the tank pickup out to check and replaced the squeaze bulb and all the rubber hose from tank to the filter on the engine.replaced that filter too.it's now back to it's initial situation where it cold idles ok and we need to take it easy for the first mile or so before getting on plane but only one or two steps needed.We run on gas station gas same as our cars but are in Md where there is a max 10% alcohol.your thoughts on what to check next will be much appreciated. | 
