Hey there,
My wife has a 04 Stratus SXT that the heat is acting up on. When sitting idle in park or drive the air doesn't really warm up much. As soon as I start to drive the air heats up pretty good. When I come to the next light and sit idle, the air is cool again. Would this be a thermostat problem or something along line of the Heater Core? I was wondering if anyone here has seen this issue before.
Thanks for any help or suggestions.

 

Thermostat would be a good guess also the cheaper of the two ... I'd do a flush and fill and thermostat change and new radiator cap ...

 

sounds like t-stat does car have a temp gauge?