Exhaust section (EX) in the service manual clearly shows in schematic that O2 sensors are removable and also describes removal and install procedure.

 

Thanks, that's what I figured, I just couldn't get to my manual easily to prove it (still haven't transferred it from my old pc).

 

i just replaced my 02 sensors(driver side) and did not have to replace cats. i would buy aftermarket cats(fast intentions) and see if that fixes the issue. if that does not work pull up the code and replace the sensor. its a pain but will save you money in the long run. both 02 sensors for drivers side was $320 and the F.I. cats are a little over $500. good luck and hope that helps a little

 

Try replacing the O2 sensors first before having to shell out duckets for replacement cats. I've had to replace one of the O2s after doing before and you can get it from Nissan for a few pennies cheaper than buying at Infiniti (same part number), at least in some cases. Don't let anyone tell you that in order to replace the O2s you have to repalce the cats because you don't