I pulled the front rotors off yesterday and inspected the bearings. I intended to replace them but they looked like replacement barrings and were in great shape. I tightened the barrings down with the calipers off so I could get an accurate amount of torque on the bearings and that seemed to help with my front end vibration.

I also replaced the O2 sensor with a direct fit Bosch sensor.  Do you think the old one was shot?