Mitsubishi Repair: idle and temperature problem, coolant temperature sensor, timing belt replacement

Question
I have a 1995 Mitsubishi eclipse GS -not turbo- when i have the heat on and i am doing normal speeds like 20 to 30 the heat seams ok. but when i go on the express way and i'm going faster the temperature starts dropping and instaed of hot air it blows cold air. idle problem. when i'm driving and come to a stop light the rpm stars to drop below the 1 and very close to the zero. and the car eats to much gas. If I change the coolant temperature sensor will this fix my problem?

Answer
Johnathan,
Try getting a new thermostat and a coolant flush.  If your coolant sensor was bad, it would usually cause your check engine light to come on.  As for your idle issue, you should have a mechanic check the ignition timing to see if it properly set.  You may be due for a tune-up or even a timing belt replacement.
Good luck!