My 2004 xterra is throwing the code p0430 (below threshold on Bank 2). I have heard that replacing my o2 sensor might be the way to go before replacing the catalytic converter. Anyone have experience with this code? I have cleaned out the engine with seafoam in the vacuum line and tried resetting it but it keeps returning.

And if I do replace the 02 sensor, do I need to remove the front drive shaft to get out the sensor that is downstream?