This, you need a compression test or leak-down test, the valves are known to wear away on some engines.

Those are important questions, if you want an actual answer to what you've posted, you're going to have to give a *lot* more detail.

 

FYI,

Bosch recommendation is to change out O2 sensors every 100k miles. Bosch are original equipment on mine.

Upstream (S1) sensor output is used to adjust fuel mixture once the engine is warmed up.

I don’t know how long to expect them to last.
My O2 bank 1, sensor 1, failed at well over 100k miles and both were replaced. Might change out my S2 sensors due to age also.

2011 XLT Screw 4x4 3.5l 3:55LS

 

Meh, YMMV for the down-streams, they're pretty 'dumb' and aren't doing anything but telling the computer if your cats are operating or not.

 

I have 4 new ones sitting in my garage. 201k miles on the OE. But fuel trims are perfect, and everything else looks great, too. Haven't quite decided whether to change them out.