just finished up a swap...we are missing one sensor...we can only assume it was originally mounted on the firewall...on my way now to look at it. just wanted to know if anyone has thoughts/ideas as to what it might be. also to anyone who has done this swap...how are you dealing with the secondary o2?

 

Well did you start it up? Start it up and check to see what code the ecu is throwing... that will tell you what you need.
As for the second O2, you won't need it IF the engine is OBD I.