My 2000 Kia Sportage overheats when it gets on the freeway and we're going 65 mph but then returns to normal operating temp. when I get off the freeway. It also seems to be burning through coolant but not leaking. Occasionally I can smell coolant inside the car along with smoke coming through the vents. What would you suggest the problem is?

Go to Google.com and type in "1999 Kia Sportage left rear wheel" for example

If the cooling system is functional, yes.
The ac condenser adds heat to the air coming thru the radiator when the ac is on. If the engine cooling system is weak, the extra heat will make the engine run hot.
Low coolant flow thru the radiator is a common cause.

Kia Forum

THE FUEL INJECTERS HAVE FUEL FILTER SCREENS THEY GET PLUGED UP WITH DIRT RUST EXC... THIS GREATLLY RESTRICTS THE FUEL CAUSING A MISS AND RAPID HESATATIONS

You said 65 mph @ 3500 rpm's? The rpm's are too high for that speed. Now, I do not know the drivetrain in a Hyundai, but any GM or Ford will run 65 mph @ 2500 rpm's. Are you sure you are putting the transmission in "D" and not "3"? "D" will be the third click from "P". If you are sure then try this:

Physically look in the radiator under the cap when cool, for coolant level, and check the valve in the cap for sticking. If air is present in the radiator it can't get out, and more coolant can't get in,(from the overflow). Either clean the cap or replace it and check that it is the CORRECT cap.
Radiator fins dirty, clean with a strong stream of water, not high pressure water.
Radiator clogged, try backflushing it, or replace.
Thermostat stuck open or shut, replace it.
Water pump worn out, can no longer move enough coolant, replace it.
Fan shroud broken or missing....
Electric Fan(s) not working, Check the fan, relay, fuse and engine temperature sensor's.
Belt driven fan, belt slipping, fan clutch is bad, fan blades have flattened out.
Air dam under front bumper is gone, loose, or broken. It actually has a purpose other than scraping on the driveway or curbs. It forces air up into and thru the condenser and radiator. If it's loose, airflow can actually push it out of place making it useless or blocking the airflow. Along with that, there may also be a plastic piece attached to the bottom of, and wraps up behind the bumper. If it's loose, airflow can actually push it out of place blocking the airflow. Simply reattach it with 4 or 5 screws.

Also, if the vehicle has A/C and electric fans, one fan is dedicated to the A/C and should come on almost the instant the A/C is turned on. The engine fan will run even with the key off, that is normal. The system is trying to cool itself. Hope this helps.

Kia's are bad cars and trucks first of all. Buy a Toyota, Honda or a Ford, quit while your ahead.

The KIA Sportage needs the temp controller switch turned to the heat/defrost side AND you need to hit the Air Conditioner Condenser button on the dash that look similar to a recycle symbol. It is not the same as the switch next to it that is a recirculate cabin air symbol. The button you want, normally turn green when activated in combination with the fan being turned on.

Aircon electric fans not working

if its a automatic and the engine is cold it wont shift into the last gear. the tranny and engine have to be at close to normal running temp to shift. its normal and nothing to freak over. if this isn't the case go to kia-forums.com/1g-1994-2002-sportage/ and post a thread there or look for one. great site

it is in the thermostat houseing right in front of the radiator under air intake duct and it is easy to get to and easy to change