1996 sunfire w/ 2.2 running real cold

i got a 1996 sunfire that will heat up to temp and the heat will work fine if i let the car sit there and run without driving it, but as soon as i drive it, the temp goes down to barely over 100 degrees, and it blows cold air, i changed the thermostat and had the coolant flushed still the same. please help, its freezing here in NY!

There are several items that could cause this problem but the first two things I would check are the Thermostat and the cooling fans. If the cooling fans are running all the time it will pull too much air through the radiator causing it to overcool when you don't need it. I don't believe this is the real problem since it will warm up when idling. But I would replace the thermostat again. Even new ones can be bad. It sounds to me like it is either too cold of a temp range or it is not closing. When a car idles very little air flows through the radiator causing the entire system to heat up. But when you drive, especially in cold weather the amount of heat transfer increases significantly and the engine will cool off rapidly and the heat will not work. Of course you can try the old trick of putting something in front of the radiator to block the airflow and allow the engine to run at a higher temp but I don't recommend it.

your a lucky one 90% of them run too hot

i have a 1998, 2.2l. i was at work idleing it and all of a sudden it got cold. the temp needle dropped. i drove it home after work and it started to heat up, but would fluctuate. what i'm going to do is change the thermostat and flush the system since i will have it open anyways.

i have the same problem. problem was not the thermostat, neither the cooling system, alternator. they suggested me it could be an electronical problem and suggested changing the computer below in front of the car..

Plugged heater core. Try reverse flushing it and if it doesn't work then, new heater core.

Ok help help help.... 96 sunfire, new thermostat, new water pump, new belt, heater core seems fine, if I drive it 35 or slower it operates normal, any faster and it tends to drive super cool as the other people indicated, now I've tried bleeding it, the car has 2 bleeder valves, one off the pipe infront of the engine and another atop of the engine block below the air filter it says thermostat. The dealer says this is where you bleed it from. Now I got antifreeze comign out of each one so I dont think it's not bled properly but the return hose off the engine to the radiator on the right is cold at the bottom. I want to drive it off a cliff with me inside it.... Someone please help me... I'm desperate...what could it be?

Have you tried replacing the radiator cap ?

Just a thought.