weird issue, what do you guys think?

So today I swapped in a tilt column, replacing the air bag column that a previous owner decided was better than the original tilt column my car came with notnice:) So anyway, I decided while I was at it, I might as well change the oil too... well my long tube header is in the way of the drain plug so I usually use a pry bar to nudge the header out of the way so that I can access the drain plug. This requires me to unplug the O2 sensor so that I don't damage it. Long story short, I changed the oil and plugged the O2 sensor back in and decided to go for a ride. 10 min or so later the car is sputtering, idle is terrible, and it falls on its face during acceleration. I checked the Anderson PMS controller and it shows no reading from the O2 sensor. Anyone have any idea what could have happened? I crawled under the car and it seems like the sensor is seated correctly. Anyway, I'll have to jack the car up tomorrow and get under there and take a better look, but I wanted to see what you guys thought.