p2196 o2 sensor code help

[cg91]

Hey all!

Got a code going right now that is p2196 "o2 sensor biased/stuck rich bank 1 sensor 1"
Tried searching around but couldn't find anything that quite fit my troubles.
Little background....just put in a new HFC about a week ago, have an o2 sensor spacer for the second/rear o2 sensor. Was fine and then the code popped up. Also seems a little rough in park, but only sometimes(rpms go 900/800/900/800/900/800). No bad smells, just normal exhaust. Tried to clean the MAF and the first/front o2 sensor. Had the battery unhooked for it and the code is now back. Any ideas? is there a way to clean the o2 sensor/would that even help? am i even focusing on the right one, or is it in fact the rear sensor?
Any help would be awesome! Thanks!

[Okedokey]

Using measuring blocks to test the O2. I would suggest you need a new O2 B1S1.

[cg91]

Using measuring blocks to test the O2. I would suggest you need a new O2 B1S1.

Thanks! unfortunately I don't own a scanner myself, but I figured I would have to replace it. When you say B1S1 is that simply the first o2 sensor? or do i need more than just that?

[Okedokey]

No, just the sensor and possibly a sensor removal tool and anti-seize grease for re installation.

[derrek]

your primary 02sensor is upset, replace it.

[cg91]

Awesome, thank you guys for the verification!

[happymonday]

Did you solve this? I have exact same issue. Replaced pre 02 and code still came back.