Thank you that was very helpful. Sounds like it can really only be one thing a faulty 02 sensor or wiring. With 30k miles on it I'm surprised it would go so soon but I'll swap itbout and see what happens.
I just jacked the truck up and looked at the 02 sensors. The one after the rear turbo had some chaffing on a black wire right at the top of the sensor. Is this bank 1? Where is the number 1 cylinder on the ecoboost motors in the front or back of the engine?
For transverse engines (side to side), firewall side of engine is bank 1, radiator side is bank 2. For longitudinal engines (as in F150), passenger side is bank 1, driver side is bank 2.
For transverse engines (side to side), firewall side of engine is bank 1, radiator side is bank 2. For longitudinal engines (as in F150), passenger side is bank 1, driver side is bank 2.