Money is tight right now so I haven't picked up a repair manual. can anyone tell me where the O2 sensor is on a 97 f-250 extended cab with a 351? I've looked from the manifolds to the cat and I cant see it any where.

 

Should be right before the flange that the cat bolts to. It's in between the two pipes

 

^^Correct. It's in the piece welded between the pipes at the flange and points straight up. The plug is up near the tail shaft of the transmission, kind of a pain to unplug.