i have a 98 expedition 4wd with a 4.6 and it's has a cel and i used a code reader and it's showing a p0156 code and the book says it's bank 2 sensor 2 o2 sensor now i think bank 2 is on the drivers side but auto zone says it's on the passenger side who's correct so i can remove the correct sensor thanks

 

On a Ford. bank 1 is on the side where cylinder #1 is and bank 2 is on the side where cylinder #1 isn't.

On the Expy, cylinder #1 is on the right bank, aka the passenger side.

 

its the rear sensor (#2 ) on the driver's side (#2)

 

thats what i thought thanks