What does the vehicle do/act/respond) when the O2 sensors goes bad

Fairly common on the 5.3L + age and mileage .. Revised gaskets available... Lot of customers prefer not to repair... Personally, I would have to fix it!

You aren't lying, there is one in a Suburban two streets back that is doing the same thing. Owned by one of my fellow service-members, and he refuses to fix it. Instead he bought a remote start so he doesn't have to listen to it warming up... almost comical.

LOL .. Been easier & less expensive to fix it!