Hatterasguy,

I would first swiitch the #4 injector with another cylinder and see if the noise moves with the imjector. If the noise moves, then its a bad injector. If not, its something else that rebuilding the injector won't correct.

As far as the GP, if the engine starts easily they are OK and don't need to be replaced. Did you do a resistance chaek on the GP? If one or 2 are different from the others, you might replace them and see if the miss goes away.

P E H