location of oxygen sensor called bank 1 sensor 1

Bank 1 means where number 1 cylinder is. sensor 1 is the O2 sensor upstream from the cat not after the cat.

where is the oxygen sensor gmc yukon xl part #13779

drivers side

where is oxygen sensor ideintified bank 1 sensor

Where is the oxygen sensor identified as bank 1 sensor 1 located? I need to replace it, but don't know it's location. 1999 oldsmobile intrique 3.8 liter engine

where is it loacated on a 2004 grandam 6 c

the b1s1 is located near the firewall