O2 sensor causing bank 1 too lean?
 

I have a 2004 GMC SIERRA 5.3L vortec. Plugged in my Actron 9185 scanner, code is P0171 Bank 1 too lean. So I viewed engine datastream and found O2S11 v is a steady 0.000. I assume I have a bad drivers side Pre-catalytic converter O2 sensor? I also get an occasional random\multiple cylinder misfire. but I believe O2 sensor is causing this as well, Just wondering if I am right or should I troubleshoot elsewhere.

posted in wrong area, sorry