starts rough sometimes,smokes,and smells like gas is burning rich or strong? on 2000 Oldsmobile Alero

Car only sometimes starts off rough. After I let it run it will start to run smoother. But while it is running rough it smokes and smells like the gas is burning rich or stronger. Also the warning light comes on. I fill up the antifreeze at least every 100 miles or so. So is is a sensor or a bad radiator cap.

Asked by for the 2000 Oldsmobile Alero