Injector or Harness or FICM?

Merry Christmas!!
Had injector 7 go bad. failed buzz test. I cleaned the spool valve and replaced the coils from another injector I replaced that had a cracked tip, and reinstalled. Had much better (but not full) power, less vibration, but still failed power balance (cylinder 7 contribution). Then I swapped Parts back to injector with cracked tip, and swapped the tips. Now has full power (as far as I can tell), but still gets cylinder 7 contribution code. Because of previous power surges (didn't notice the decline part) and engine occasionally completely shutting down for a split second (hiccup), I suspect the injector harness. Could I have a bad harness that shows as contribution fault, but not circuit high or low? Could this 03' have an otherwise good FICM and only trouble with one cylinder? Which scenario is most likely? Advice?

03 with 275K miles. Stock except for atlas 80 ficm, gutted cat, EgR gone. Engine harness previously failed with sync issue and replaced.

Thanks.

Check the connections on ficm there a bitch to get hooked back in.

Still trying to figure this out. Is there any way to test the ficm at one cylinder only? I'm thinking a low voltage to one cylinder may have caused that injector coil pack to eventually fail. I have heard the older ficms can have one cylinder go bad.

I tried another ficm and it ran the same. I was going to swap injector 1 and 7 to see if it followed. Injector 7 (the one I switched parts on) had the bolt that holds the coils on broken. Since I just returned my other core, I had to put in a new injector.

I put it back together and it ran worse. Two cylinders weak in power balance. New codes - injector 4 and 7 circuit low. This must have just happened. replaced harness and runs great.