Truck is obviously running rich. it is a 2001 Ram 5.2L. I know the code is saying the O2 after the cat is reading high, could it be that the O2 before the cat is bad and causing this?
What is the most likely cause, is the fuel pressure regulator worth investigating?
Could a bad Cat cause anything like this?

The truck is kind of a turd, does lots of downshifting in cruise. I know its only a 318. I've never had a Dodge period so I don't know what to expect. I know that my 350 chevy had much more torque.

Thanks for any help!

 

Replace both sensors. But also do a search here for "plenum". It will be the reason the cat is or probably getting clogged and for the poor performance.