No heat

I have noticed my temp gauge going up then down and up and down. I i will turn the heat on and it is warm at first then it turns cold... I have no ideas

I have noticed my temp gauge going up then down and up and down. I i will turn the heat on and it is warm at first then it turns cold... I have no ideas
Some Taurus's have had troubles with the water pump. But I would change the Thermostat first, the easiest to do, and the cheapest.
But you can also do some diagnoising: Does both heater hoses get hot?
Is there coolant in the overflow tank? Look for leaks. Fix those first.

Temp guage goes up, thermostat opens, then temp guage goes down, engine cools off, thermostat closes, engine temp rises, temp guage goes up and so on. Heater not working is indicative of a clogged heater core. Check both hoses going to the heater core and see if they are hot.