Jimm 1/20/2013The white smoke out of the exhuast is usually an indication of a leaking / faulty cylinder head gasket - that is the engine is leaking coolant directly into the combustion chamber.
To check and confirm this - have an inexpensive compression test performed to check the cylinder sealing integrity.
Sarah Spark 1/30/2013Your exhaust system seems to have an issue, the heating and the white smoke. You need to have it checked, There could be a leaking of gases, leading to incomplete combustion hence the white smoke. Consider repair or replacing the exhaust system. There are some fair deals for exhaust systems online like http://4wheelonline.com/jeep/Jeep_Exhaust.48283