OKay for the sake of argument I swapped the driver front O2 with the passenger front O2 and it is still the same thing. Bank 1 is Lean. I dont understand how Bank 1 is super lean and Bank 2 is only slightly lean. I mean it idles at 21% on Bank 1 and 2.3% on Bank 2.

Something has to give.

 

Okay I got to messing with the truck some more. I may have an exhaust leak where the header meats the transistion pipe to the Hi Flow CAT. It is tight but I think it is out of alingment. I bounced the truck through a decent size ditch a few days ago. That is about the time this all started. I got under the truck earler and there is an audible ticking comimg from the area of the header to transistion pipe ball and socket flange. I am gonna drive the wifes Tahoe to work tonight and work on the truck in the morning.