Do gas-saving devices really work?

A new study has revealed that certain "Gadgets" that are designed to stretch out your mpg may not be as reliable as consumers think... which ones can you really trust?

Garage mechanics and auto enthusiasts are likely to be familiar with a certain type of advertisement. Appearing in car magazines and throughout car-focused Internet pages, these ads offer a range of products with a similar claim: that by bolting on, plugging in or pouring Product X into your vehicle, you'll experience an amazing boost in mileage efficiency.

Mileage-boosting gadgets have been around for years, and they seem to make a comeback every time gas prices spike. While the packaging may change to fit the times, one large question hangs over these products: Do any of them actually work?

Read more:
http://auto.howstuffworks.com/fuel-efficiency/fuel-saving-devices/gas-saving-devices-work.htm