My 03 4.0 explorer has an intermitten check engine light. Code is P0133. sensor 1 bank 1. I believe replacing the O2 will eliminate future check engine issues however I dont know which o2 I need. Any help would be greatly appreciated. thanks!

 

Bank 1 is on the passenger side, and sensor 1 is the 02 sensor before the catalytic converter (upstream).

 

thanks V8SHO!