With gas prices still high, readers have asked us to weigh in on products that promise better fuel economy. We tested three: Fuel Genie, Platinum Gas Saver, and Tornado. Our advice: Don’t waste your money. They don’t work. This isn’t news. We’ve tested such devices over the years and have not found any that improve fuel economy. The Environmental Protection Agency, whose Web site lists scores of devices that the agency has tested in the past 30 years, including the Platinum Gas Saver, has had similar results News source: Consumer Reports The Fuel Genie, $90, which promises more power and better gas mileage, is a plastic device with curved blades that fits inside the air-intake hose. The airflow is supposed to allow for better performance. But in our tests with a 2004 Toyota Tundra and a 2004 Dodge Stratus, we saw no significant improvement in performance or fuel economy. The Tornado, $70, is a similar device made of stainless steel. It is the same product we tested for a July 1999 report, when we said it didn’t improve power or gas mileages in two test vehicles. The Platinum Gas Saver, $119, includes tubing and a plastic reservoir containing liquid. It is the same device we tested for our report in February 2001. You connect it to a vacuum line leading to the intake manifold. The manufacturer says that microscopic platinum particles from the liquid are sucked through the line, helping your car burn gas more efficiently and cleanly. In our previous tests, there were no changes in fuel economy after we installed the device in two test vehicles. The bottom line: The best way to get the most from a tank of gas is to follow the vehicle manufacturer’s service schedule.