Slim

What have y'all done when the check engine light comes on indicating (Code 0303) that the front O2 sensor is whack? The FSM gives me nothing, unless I had a Consult. It also doesn't specify whether the "Front" O2 sensor is on the front (towards the bumper) part of the Y-Pipe or on the back part of the Y-Pipe (they consider the one on the cat to be the rear). Maybe I'm just missing something in the FSM, but it's confusing as all hell...