Why does white smoke come out of your muffler?

Answer

One potential cause is too much gas. It may be running "rich". Your car may also be burning a little oil.

White smoke is usually water or antifreeze. If you are loosing coolant from the radiator, it's probably a blown head gasket. If not, it is just condensation in the exhaust pipe that is evaporating as the pipes heat up. If the car is running too rich, the unburned gas will cause black smoke and burning oil smoke will be blue.