Need some help sorting out some problem codes.

In the KOER i'm getting a 111 ( all good )
In Continious memory i'm getting codrs 172 and 177
In KOER i'm getting 137

The check engine light is coming on after a few minutes of driving. I just last night replaced the lower intake gaskets to deal with a coolant loss problem and oil in my coolant. I just purchased the truck and am looking to get it running smoothly before i drive it. Thinking of checking for vacum leaks and checking the fuel pressure regulator next. The engin has 2 o2 sensors and i am wondering to which sensor the codes refer to. The one on the passenger or driver side? Thanks for any help that you can provide.

 

Welcome to FTE!!

Your getting two rich codes and a lean code, I think your on the right track, I would start by looking at the stability of the fuel pressure too.