Yep there is.

There's a product out there called (believe it or not) Miracle Oil that you use in a diesel - you can put it both in your gas tank and in your oil as well (you gotta love a diesel car.)

Basically it keeps the gas from gelatenizing in the winter time (the parafin in the fuel solidifies at very low temps - that's why there's a "winter grade" of diesel with less of the stuff in it.) and it'll also prevent algae buildup (the critters love the parafin) in your tank.

I would buy it in big 2 gallon jugs at the truck stops and put in about 12 ounces per tankful, and that baby ran like.... er.... a dumptruck loaded with nitro, rolling across cobblestone.