in the winter, my car runs sooo cold. so i changed the thermostat to a 195, and filled the fluid. it ran really good for a first little while giving lots of heat etc. now after a week, the heat has become to blowing cold air again. its hot when im driving, but when i stop it gets cold. any suggestions. i dont think its leaking, have not noticed anything in the snow. now it could be becuase where i live it gets to be -40 or more, but i think the engine should keep warm.

 

You're driving your Trans Am in -40 weather? Wow.

Apparently at those kinds of cold temps, cars won't maintain their heat while idling. http://www.metrompg.com/posts/warm-up-idling.htm (read near the bottom)