02 sensor signal stuck, lean bank 2 sensor 1.
i have replaced with a new o2 sensor and this code came up. the code was gone for about a month and now back. what could be the problem.
thanks

 

What brand O2 sensor did you use? Anything other than OEM or Motorcraft seems a bit incompatible with Ford ECM's which might be at the root of this return.

Is the connector or any wiring visibly damaged, perhaps not making good contact along its length?

 

its a bosh from auto zone

 

Bosch O2 sensors from anywhere have been known to cause problems in Fords. For most sensor replacement its always highly recommended using OEM or Motorcraft.

More specific info might be found here: Modular V8 (4.6L, 5.4L) - Ford Truck Enthusiasts Forums