Second time my SES light has indicated an O2 sensor with a slow response. I changed the sensor about 4 months ago, and now it says it needs another sensor (bank 2). Is this typical after changing one sensor? Will I eventually have to change all the sensors? I would appreciate some feedback if anyone has experienced this problem. Does this effect gas mileage? Thanks!

O2 sensors do have an effect on gas mileage..... You can replace them one at a time or all at once...

I believe that is a rear sensor code. Those o2's have no effect on fuel economy . They are only for cat moniter. The thing is if you have a 2000 2001 or 2002 pathfinder you can not simply replace the o2. You have to replace both rears as a set and have the ecm reprogrammed to prevent them from burning up again. The problem is the o2 sensor heaters are coming on at to high of amperage when there is moisture on them during initial start of. That moisture is causing them to burn up. The new ecm program stages the amperage application to help dry up the moisture on them.

I had the same code pop on me; read what I've posted below for others:

I think I am the first to figure this problem out. About 1.5 years ago I ran into funny problem codes and this same stalling problem. I took it in 3 times to the same Nissan Dealership and they couldnt' figure it out. They kept giving me new "fixes" to try. I finally took it to an independent repair place and the guy figured it out. The Turbine Revolution Sensor on top of your Transmission is probably faulty and is leaking tranny fluid through it. Because of this leak, you will probably get funny problem codes down the road here. The tranny fluid flowd down the wiring harness of this sensor into a whole host of other harnesses, triggering Intake sensor issues, O2 sensor issues, etc. The stalling is due to the low transmission fluid. Check your tranny fluid. If it's low, then fill it up. Your problem should go away. Good luck. Let me know if this fixes the problem. BTW, the metal housing blocks the visibility of the tranny fluid on the ground until the leak gets severe, like mine did. Good luck and please repost to let me know.

~Blessings.