I don't quite get the whole Bank thing, but I've got two codes..:

P0141 - Heated O2 Sensor Bank 1 Sensor 2
P0175 - Bank 2 Rich

There are two different banks giving codes, one of which says I am running rich. It's a 1999 Ranger 4.0L V6.

Tomorrow's plan is to check the spark plugs, check that hose elbow behind the oil fill cap, and check the fuses for the O2 circuit. Any other ideas?

 

Welcome to FTE. I'll see if I can get things started.

P0141 = cyl bank one/passenger side, #2 O2 sensor (after cat O2 sensor), heater circuit has a problem.
P0175 = cyl bank 2/drivers side #1 before cat O2 sensor, is indicating that cyl bank is running rich. SO, maybe a faulty, dirty, leaking, stuck open fuel injector belongs on your suspect list.

Since we don't have O2 sensors monitoring each cylinder & to maybe find the suspect fuel injector, remove & inspect each drivers side spark plug for carbon fouling. The suspect injector will be in the cyl with the carbon fouled spark plug, so remove, inspect, clean, or replace that injector.

Some trouble shooting thoughts for consideration, let us know how it goes.