UV dye with a fuel leak is interesting. Never heard of that before. As the fuel runs all over or sprays even, how exactly does that tell you where it started? In any case, for the throttle shaft I think that a leak there means the at a minimum the pump has to come out. I cant see any way to fix that bushing without taking it apart and for most people, myself included, taking apart the IP to that degree is out of my scope.