2000 silverado 5.3 o2 sensor help

hi, i might sound a bit stupid but i got a code reading that says i have a bad o2 sensor. It says it is bank #2 sensor #2 but honestly i dont know what that means. I have been to the ZONE (auto zone) and the guy there could only tell me that it was one of the ones behind the cat...which sense there are two i dont know if its the driver side or passenger side one that has gone bad. i would just change both and save the trouble but at this time i can only afford one since they arnt cheap.

hi, i might sound a bit stupid but i got a code reading that says i have a bad o2 sensor. It says it is bank #2 sensor #2 but honestly i dont know what that means. I have been to the ZONE (auto zone) and the guy there could only tell me that it was one of the ones behind the cat...which sense there are two i dont know if its the driver side or passenger side one that has gone bad. i would just change both and save the trouble but at this time i can only afford one since they arnt cheap.

O2 sensors are good for 100,000 mi.... you have 4 sensors driver side is called bank1 pass. bank 2.........when it is bank2 sensor 2 this means pass. side downstream sensor n/g.....

if you replace you must use the same sensors that came with vehicle or you risk further codes, also don't be surprised if you catylytic converter is going to get plugged or loose effeciency.....a bad o2 can damage the catylytic converter this is the usual cause...poor gas mileage also...unfortuately they cost 100.00 ea...