The mechanic that installed my Stillen Y-pipe, never put back my secondary Upstream o2, which i'm aware i don't need essentially because it doesn't affect PCM output.

But i'd rather have it there because i have the money, and for peace of mind. So i'm having a little trouble finding where in fact the secondary sensor's harness plugs into?, is it anywhere near where the inital o2 plugs in?; in front of the engine in the engine bay, or is it somewhere underneath like the post-cat sensor?

thanks

-=sMh=-