My temperature gage will jump up and back down frequently, and I've noticed some white smoke coming out of the hood of the car. Heat and a/c blow air, but there is no temperature regulation in them.
My car has 169000 miles.
This sounds unfortunately like a blown head gasket problem. The fluctuation in temperature and white smoke is usually a sign of this. I would suggest having the coolant tested for traces of combustion gases which will indicate if the head gasket is compromised. If this is in fact the case, I would suggest having an certified technician, such as one from YourMechanic, come to your home to diagnose the smoke firsthand and help you make the necessary repairs.