Rough running and restricted performance

A few weeks ago I experienced a restricted performance light and the code said that it was a faulty coil pack. I replaced all of the coils and the car ran well for a couple of days and then I got another restricted performance light and this time the code said that it was because ther was no fire to #3 fuel injector. I took it to my trusty mechanic who said that it was a broken wire. He fixed that and the car ran well for another couple of days and now believe it or not I have another restricted performance light. Before I take the car back for another expensive fix does anyone have any ideas or experience of such events.

What are the code numbers, year and engine?

Hi Bob thanks for replying. The car is an 03 with the 4.2 engine
4 codes

1 P0303 #3 cylinder missfire

2 P1313 no dtc def found

3 P0203 injector circuit open cyl 3

4 P1000 dtc no def found

Thanks Len

P1000 probably not relevant. P1313 is related to P0303 due to P0203: Either it is in all the wiring from the ECU to the engine or the injector died this time. Maybe -guess- the coil and injector are on the same circuit as in some other cars. If one goes down, the other won’t do anything either. If it was #3 the last time you might want to swap the injector against another random injector and if the code moves, good. If not I wish you the best of luck and hope it turns out to be a flimsy connector.

David