I just replaced my front O2 sensors because bank 2 sensor 1 was throwing a code. Now I have a new code now bank two sensor 2 is throwing a code.

Is this because the PCM is now seeing a new reading?
Should I just clear the codes and ignore it to see if it will go away?

 

its always worth a try to clear the codes and see if they will stay gone.
the rear O2's don't really do anything except double check that the cat is doing its job. don't waste money on them if you can help it.