wallybirt

Thank you all. Replaced both  upstream sensors, edge drives like it has new engine.

Thanks for your reply,  I have a 2011 ford edge with a  3.5 motor .Looking to replace 2 sensors .One in front of motor and one at the back. i think they are both upstream . Just not sure.

Just wondering , Are bank 1 and bank 2  sensors the same sensor or are they different . I am about to replace one on front and that dirtly little guy at the back of engin..  Thanks.Norm