I replaced the 02 sensor today thinking I would have some luck with the car idling rich, and boy was I wrong. I'm currently only getting a knock sensor code, but the damn thing is puffing black smoke at idle. I used almost half a tank of gas today driving around troubleshooting...and not even going over like 40mph. Is it possible I have a fuel line switched or something retarded like that?

I dont even run a o2 sensor ? I doubt the o2 is your problem man..