Left and right bank running lean, what O2 sensors do I replace

Hello,

This vehicle with the 3.0 V6 has 3 oxygen sensors.
Two of them are upstream or before the catalytic converter and one downstream after the catalytic converter.
The two upstream sensors are divided into bank 1 (left hand side) and bank 2 (right hand side).

Please keep in mind that depending on the code it could be a related item and not the oxygen sensor that is triggering the engine light.

What is the code that you have?

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.