2003, 4.7, club cab sport. My code came up as bank 1 sensor 2 so I bought a downstream one to install. Climbed underneath and there is no cat on the driver's or passenger sides as in all the photos and diagrams I have seen, there is only one and it is further back after the two pipes merge. At that location there is an up and downstream sensor so I replaced the downstream. Have not reset the code yet or run it for any length of time. Am I missing something with the 2 banks and the location of the sensors? Thanks

 

if they don't run dual cats...b1s2 will be the lone post cat sensor