I am unsure on which side of the engine is bank #2 on a Duratec. If I had to place a guess, I would probably say the side near the firewall.
On the Zetec, there is a O2 located in the manifold directly before the cat, and one after. Not hard to find, looks like a big metal spark plug. The upstream sensor would be located (I would think) before the precat. I think someone mentioned that is is near the Y-pipe under the car.
Sorry I couldn't have been more help.
This is a question for someone with a Duratec now.
EDIT: No P1151 is not the part number.
