01 Ranger 3.0L rich on one bank

I have a 2001 Ranger 2wd, 5spd with a 3.0L (non-flexfuel vin "U")

I bought the vehicle with a gas tank full of water as a repo.

I removed & drained the fuel tank & lines, removed injectors & refilled gas tank & purged out lines with fresh fuel by jumping FP realy then re-installed injectors. replaced plenem gasket, air filter, all fluids in vehicle also. New motorcraft single plat plugs & wires. Also compression tested about 170-180 across the board.

Vehicle will start & run fine for a few minutes (maybe 10) and it will gradually start missing after pulling out the injectors. The next, and following times it will start & run like crap.

Scanned vehicle to find no codes (yet), but a -18 ST fuel trim on bank 1 and a 2 ST fuel trim on bank 2. bank 1 had a sluggish 02 sensor would move very little and never under .800 (very rich). bank 2's 02 sensor was quick & moved in between .073 to .900 when you would rev or snap throttle.

I pulled the bank 1 upstream 02 sensor to find it pitch black (so I think the rich fuel reading is accurate), pulled bank 2 to find a normal colored sensor.

My thought is that I had a bad injector, so I swapped injectors side to side -- same problem.

My second thought is that I had sticky injectors, so I replaced the entire set of injectors that came out of a good running low mileage 3.0L

Still the same problem....!!??

Please, enlighten me with any ideas you may have.

Thank you!!