P0304 code

What is your question?

I said earlier new wires, new plugs gapped properly, new ignition coil pac, had vacuum checked, auto zone does not believe it is a crankshaft monitor, at highway speeds no hesitation so not the fuel filter they say, so they believe injector #4 is misfiring randomly ..because the light goesout at time and then comes back on 30 miles later i now waited after the clear and return of lite on then drove another 100miles...it is on again ...so what is the likely hood it is an injector on cyl #4...thanks bioman