There's an infomercial running that's advertising a very interesting device. It's called the Tornado Fuel Saver. It's supposed to increase horsepower and fuel mileage. Of course, there is a slight disclaimer...
Your results will vary. These tests were completed in a laboratory under test conditions. Mileage improvements, if any, vary widely depending on driving habits and the model, engine, and condition of the vehicle.
I haven't bought one myself, but here's some things I find interesting about it. They don't tell you what laboratory did the testing, so you have no way to verify the test data, or find out what the test conditions were. If it does what it says, wouldn't the auto manufacturers have done this already? Form your own conclusion, but something that sounds too good to be true usually is.
4 hours ago