So my exhaust started rattling a few days ago. Being out of town with work I couldn't fix it at the time. Eventually that turned into a terrible sounding exhaust leak. A friend here let me borrow his garage last night and come to find out one of my wideband sensor plugs had backed it's way out. Luckily his father-in law had a bad O2 sensor that I plugged it with temporarily.
So just a word of advice. Check your plugs. I had mine cranked down pretty tight but they still backed out on me.