2000 3,8 impala misfire

I have a 2000 3.8 with 215,000 miles ( yes that is correct origanal motor)
I have been recieving a 304 code (cylinder #4 missfire) I had to change the upper and lower intake manifold gaskets and while doing this i sent the injectors out ot be cleaned, I replaced them in no special order and now i am recieving a 302 (cylinder #2 missfire)

I have changed all plugs, wires, coils, with the price of injectors at $150 each i would like to see if any body else has had the same problem or might be able to guide me in the proper direction.
Looking to get 300,000:grinyes:

I would bet that the injector that came out of cylinder 4 (causing P0304) was put back in cylinder 2 (now causing P0302), so that injector is most likely the culprit.

The injector would also be my best guess. Are those original injectors? Some 3800 Series II's have been known to have injector troubles.