I didn't start the pathfinder for one day and the Service engine light soon light came on and after some initial check
looks like the 02 sensors needs to be replaced. (the code came back for that)

Then for 10 days the light didn't come on... The 2nd time (10 days since the initial check) also I didn't start the pathfinder for 1 day then the light came back on and now stays on.

There are 4 02 sensors in pathfinder right? Does any one came across this issue, the cost involved? where you get 02 sensors...etc? Any comments appreciated.
Currently have ~91K, I am the 2nd owner does the warranty cover this?

costed me 150 each. mine was doing the same thing. the light was coming on and off. since the change the ligh has come back on and off so i needa bring mine back in to check. this service engine light problem sucks.

I have the same problem on my 01. The dealer wants 100 beans just to check it out. What's the deal here?