C320, Getting over rich on bank 1. Live data showed -4 to -5 long term on bank 1 but bank 2 was 0 to +1. On urgent acceleration, short term 1 would go to max, accel limiting came on w/eng light.

I guessed one or 2 injectors were at fault so I swapped 1 and 2 banks. cleaned the seals and spayed out the input side with brake cleaner, silicone lubed the seals. no big deal, just sprucing and dressing be fore installing.

To my surprise, the problem did not switch sides, but it did get a little better: -3 to -4 long term on 1 and +1 on 2. Stomping it did not throw an error and did not get to rpm limiting. I didn't rev too far since i wasn't happy with the -3 to -4.

So what should I try next? what would cause the right side to pump in too much fuel while the left side is a little lean? Could it be a sensor issue?