More problems...
 

So, as you may or may not know, my o2 or cat went bad, and threw a CEL. Well, today, when I was taking off somewhere, I saw black smoke when I looked into my rear view, it sounds a little deeper/louder, and under light throttle, it sounds like something to do with the exhaust is rattling... almost like tiny metal pieces inside the cat, or at least what someone would expect it to sound like. My buddy Dillon says I might have blown the packing in the cat. My friend Corey says that's impossible. Wtf is going on with my car?

Sounds like the cat to me!
The cat is filled with honey comb type material and when it melts down the pieces break apart.check the back of your car for metal particals or flakes.

you would be running rich if your exhaust manifold o2 went bad, rear o2 (who cares), sounds like your cat took a boom boom.

My cat went boom fast! So I just got catless dp, as far as black smoke my car does it all the time at WOT