V8V Running Rich or Bad O2 Sensors?

Ran the diagnostic. Looks like an O2 sensor issue.

Error 4/4 - P2198 Generic O2 Sensor Signal Stuck Rich Bank 2 Sensor 1
Error 3/4 - PO153 Generic O2 Circuit Slow Response (Bank 2 Sensor 1)
Error 2/4 - P0153 Generic O2 Curcuit Slow Response (Bank 2 Sensor 1) *SAME AS ERROR 3/4 (I find this odd...)
Error 1/4 - P0133 Generic O2 Circuit Slow Response (Bank 1 Sensor 1)

The diagnostic tool I picked up has a Non-Continuous Test option. I can run on O2 sensor B1S1 and B1S2. Any use?

Would you change your plugs given the rich condition (perhaps they are partially fouled)?