Which o2 sensor is #21 for ls v6????

[prestone1011]

So my damn cel light came on so i took it to my mechanic and he told me o2 sensor #21, and come back monday.

Few questions:

1. I know there are 2 banks, with 2 sensors each. Which one is #21??

2. Which part would anybody recommend? Any links??

3. Any advice on an install??

Any feedback would be greatly appreciated. Thanks.

 

[lincoln00]

that might be bank 2 sensor 1.. but i have never seen it like that... might have been typo unless he said that.. could have been talking in hexadecimals??

 

[NYC LS8]

Obviously it's the 21st O2 sensor that's on the car. Duh.

 

[rickztahone]

Obviously it's the 21st O2 sensor that's on the car. Duh.

it's so obvious, lol. seriously tho, i'd bet on bank 2 sensor 1