Rough Running

HI my car has driven great for about a year then this morining i went to start my car and the thing ran like crap. It was almost like the car is running on half of its cyclinders. I have no idea whats wrong. I did the fault code thing by sticking a fuse in the fuel pump relay and i got code 2131 but that has nothing to do with the engine.Also there is a liquid comming out of the exhaust and its not oil or gas it doesnt have any smell, it looks like water. Could somebody please help me out

Thanks Alot