I have two codes thrown on my 06 g35 coupe with 112000 miles. Both are for bank 1 and bank 2 sensor 1 so the upstream o2 sensors. My questions is what are the chances of this happening that both two sensors went bad at the exact same time? And could these codes be thrown from anything else? I used carb cleaner and sprayed around vacuum lines with no success too..thanks for your help! It's much needed!

Check your intake. Mine was loose with these codes....! Once tightened up no codes.

Thanks urban- I briefly checked it earlier but ill take it off and re install it tomorrow after work and report back here..hopefully this helps lol I'm kinda at a lost

usually it means a leak some where. check all your connections after the maf and even be sure to check your headers. i had a leak from a bad gasket and threw one of those codes.

also if you can get your car in the air check the wires on the O2 sensors make sure they are not frayed/corroded in any way. and check that they are plugged in snug.