where is the bank 1 o2 sensor on a 2000 lincoln navigator

does not mean the o2 is bad. it cannot adjust long term to manufactures specs. you need to find the issue and repair. then the o2 will read much better. Roy

bank 1 i think is facing vehicle is the passenger side number one sensor upstream. (IT should have 4 sensors 2 upstream and 2 downstream,2 heated and 2 non)