So I was driving home last night, and all the sudden my car starts like.. jumping/ skipping. Stalling/ running, I don't know how to explain it really. There was white smoke out of the back and it was rocking. It died as I was turning off the street so I could get out of traffic. Any ideas what's wrong? Timing chain? Water pump? Fuel pump? Oh. It's a Nissan Altima. Ideas? Anyone? Bueller?