I did try doing a search, didn't come up with many results. My car is throwing a P0031 and I have a question which side bank 1 really is? I've read passenger side and also driver's side. What all is involved in replacing the upstream o2 sensor? I'm assuming I have to pull the cat off to get access to it?

also does anyone know if 2007 g35x uses the same sensors as 2009+ g37?

I just replaced that sensor this past weeken along with one post cat. The two pre cat are the same and the 2 post cat are the same. You can contact Nissan for the part numbers and buy from them or try autozone. Dense are factory which I recommend. Also u do not need to get under the car for this and it will be the passenger side in your case. It takes ten minutes and is pretty easy. Pm and ill give u more advice if needed. Good luck

ok! thanks for the info

Ended up with this code this morning. For the uninitiated like myself, where on the passenger side is it located?

It's hard to spot from the engine bay it's on the exhaust manifold before the cat. If you look under the car it's easier to spot. Not an easy thing to get to and replace; I think mine is bad as well and trying to find a right O2 socket to fit in and get enough leverage to remove it.

Does anyone know who the OEM of the o2 sensors? I am looking at picking up Denso p/n 2349036 and want to make sure it is correct.

On a side note, is there any truth to mixing oxygen sensor brands will cause issues with trigger the SES light?

I believe the oem ones are Denso. I had a passenger side upstream fail and I bought a new one from Advance Auto for less than $100bux. make sure you have the oxygen sensor socket/wrench otherwise u'll be pissing in the wind