Visible smoke and black smoke on tailpipe

I have a 1995 Nissan altima, 5spd manual. I recently added a cold air intake, and after doing it car runs good, untill I was checking the acceleration, and rev the engine pretty high, and suddenly I heard a POP, loud enough to hear over the high rpm, then I noticed that the idle changed, its a little rough, and noticed too that, there's smoke coming off the tailpipe(never seen that before in my car), and I also noticed that the smoke leaves a black stuff on the tailpipe. Can you please tell me what I did/broke, and how to fix it. The engine now runs pretty weak on low RPM, and runs strong on high RPM, but still makes the black smoke.