Mitsubishi Repair: Overheating while idled, coolant temperature sensor, engine coolant temperature sensor

Question
Hello, I have a 2002 Eclipse GS.  I've noticed that when I am at idle my temperature gauge creeps up to hot and cold air blows out of my vents when I have my heat on.(since it is winter time). When I go to accelerate, the temp. gauge moves slowly down to the 1/2 way mark and my heat instantly comes back on. While driving it will sometimes fluctuate.  I had my water pump replaced, a new thermostat installed, a new timing belt, and a new radiator cap.  IT STILL DOES THE SAME THING!!!!   HELP......what could it be? Thank you.

Answer
Leah: Try having the computer coded it might kick out the problem, as it could be sensor. It is called the Engine coolant temperature sensor and could be causing your problem. Another thing to check is that the fans are running right that help cool the engine, do they kick on as they should. Also check to see about your air filter is it needing changing. Would there be anything keeping air from flowing through your radiator, like a bag is stuck up on the radiator or something on that order? Another thing to check would be the timing, is the engine in your car timed right? I hope one of these ideas helps you. God bless: Linda