No. It was a CAT bank 2 code or similar, P0430 code. CATs usually don't go bad unless the vehicle is burning oil (no), really bad injectors and running very rich (fuel mileage has been stable) or using leaded gas (very doubtful). I checked the pipe temp in front of and after each CAT and noted it was always hotter on exit - so the CAT is working. So went after the O2s. Probably was only 1, but being I was laying under the truck why not replace all 4! Invaluable tool is a crows foot style O2 socket - used on 3 of them, and long 22mm combination wrench - used on the DS upper - bugger to get to. Probably took the most time was getting the connectors apart on the 2 sensor wires that are in the transmission tunnel sorta above the transmission not much room there for my hands.

I sprayed the sensors well with AeroKroil about an hour before hand.

Bought from RockAuto $165 shipped for all 4 including the crows foot.