I have a '98 Stratus, when I start my car to warm it up and I turn the heat on, unless I am sitting in the car pressing on the gas heat doesn't come out. When idling at a stop light the heat turns cold until I step on the gas again. I am thinking, either the thermostat, water pump or I need more coolant or a flush. Has anyone had a similar problem or the same thing? What is the problem???? Help I'm cold!!!

 

I would start by replacing the thermostat first and see how it works.