Wondering if someone can help pinpoint exactly which O2 sensor may be bad with this code P2251. The first time I saw this code was after we put in the Driveshaft which the off-road Hpipe had to come off and be readjusted. That was around a month ago. I got under the car and messed with a couple of the O2 connections and cleared the code. It didn't come back until last night while making a trip to Mexico. I am leaning towards the first O2 sensor on the passenger side as that one is twisted and is a tight fit. Would like to see if anybody would know as I would rather not be guessing. Is there a way to check/monitor which one is bad? Should I not drive it? Thanks for any help.