I'd say check the head gasket (If you don't feel comfortable ripping the engine apart to troubleshoot this, you can always take it to your local mechanic). I have a 2003 Dodge Ram that suddenly started spewing out white smoke, which eventually got worse. Took it in and the head gasket was blown. You would also benefit from checking the coolant reservoir and antifreeze level in the radiator. A coolant leak could explain the smoke, as well as the coolant gauge level not moving

 

I dont know what was causing those problems but they have both went away now. If they come back I will do some more investigating.