I took my Cherokee off roading today and first let me say, holy cow, this thing will go where a goat would turn around and go back! I was in some particularly bad rocks and holes and suddenly it starts to idle bad, surge and run like crap, fortunately I made it home. Black smoke is coming out of the tail pipe, it's obviously running rich, any ideas?

Is the check engine light on

Yes, but it's been on a long time as O2 sensor wire is disconnected. It has always run fine though and gotten decent mileage. I have the Ford V8 injectors btw. It happened all of a sudden.

heres your problem. go get it scanned

Could be the that other O2 sensor went out also.