All of a sudden, my car has started doing several odd things. It starts up fine, but when I go to drive it anywhere it just belches smoke everywhere. I'm talking like a smoke trail that people drop back to avoid. This comes and goes regardless of engine temp.

Also, My radiator fans are on almost constantly. I haven't ever noticed this before, nor had it had as much impact on the engine.

I'll be sitting some where, in neutral (auto) idle at 1000 or more, suddenly, both fans will come on and the idle will drop to 4-500. They will either run until I shut off the car, or will kick on and off in intervals of a few seconds, affecting the idle every time. I am replacing the o2 sensor this week, and I pray that will cure the smoke disease, because I don't like it one bit.