First, there are fuel additives like the Platinum Gas Save and the BioPerformance pill. Neither works, and the BioPerformance pill has been proven to be nothing but moth balls, which are toxic.

Then there are the Fuel Genie and Tornado, which are mounted in the air flow meter of your car. They are supposed to affect the way air is sucked into the car, but have yet to be proven effective in improving mileage. However, altering the air flow of your car can make it overheat, possibly causing permanent damage.

There is also the Predator and many similar knock-off products. The predator costs a hefty $400 and reprograms your car to ignite the fuel earlier, which makes the fuel burn longer. Though the initial aim is to increase horsepower, customers have reported getting better gas mileage as a happy side effect. And these products DO work like they say. But, they're risky. When the engine burns less fuel by this method, there is the risk of overheating it. Since the car is using less gas, it doesn't have the ability to cool itself properly. Again, this can cause your engine to overheat and perhaps even ruin it completely.

No one want to save a few bucks on gas just to blow their engine!

Many mechanics are wary of all these additives and gizmos. "Yeah, you might get a little better gas mileage out of it, but you might have just taken 50,000 miles of life off the motor by trying to do it," said Larry Perry, the Magic Mechanic radio host.

The Environmental Protection Agency has been looking for and testing gas-saving products for over thirty years and has found very few that meet its standards. So be careful.