This just started today, it has happened twice now. After driving my car to the stoplight I noticed it started to idle a little rough, I pulled over into the gas station, put some air in my tire (slow leak). When I started the car back up I seen a decent cloud of smoke coming from under the hood, I popped hood and checked, couldnt see anything. While at lunch, the same thing started to happen, rough idle, I pulled over, popped the hood and started it....same white smoke frome same place, I cant see where its coming from exactly but it seems to be bottom end.