I have a 99 intrepid 3.2 169k miles on it
when I start the car up in the mornings let it sit and idle my heater is still blowing cold air but once I start driving in comes the hot air until I idle again but it doesn't always go back to cold air at idle only 3 out of 5 times I stop the car I have checked my coolant level its fine the heater core isn't leaking in my floor idk what it really could be please help

 

The thermostat or heater control may be broken.