Check your Diaphragms, see if there is any holes in them. If there isn't I don't know if I would use Berryman's to long. Lot of us use the Sea foam I would switch to that on next fill up and see if it straightens back out. Another thing which I don't know if the 05 has one but check your vacuum advance hose for any leaks. Maybe spark plugs. But anything more then that, @Flyinfool @yamagrl @bongobobny might have other suggestions too.