Platinum Gas Saver
The Platinum Gas Saver ($248 for two, free shipping) includes tubing and a plastic reservoir containing liquid. The National Fuelsaver Corporation claims the device is guaranteed to increase fuel mileage by 22 percent, in addition to extending engine life by cleaning out abrasive carbon deposits. It connects to a vacuum line leading to the intake manifold. The manufacturer says that the product adds microscopic amounts of platinum to the air and fuel going to the engine, 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, a Nissan Altima and a Ford Excursion. We followed the manufacturer's instructions for installation and ran our standard acceleration and fuel economy tests with and without the device. The manufacturer says that the device may take from 200 to 1,800 miles before it is fully effective and that for greater success, you may have to advance your engine timing 10 to 12 degrees and/or install new oxygen sensors. But those actions alone could improve fuel economy if they were not set correctly or working properly.
After 500 miles of testing in each vehicle, we saw no improvements. We also replaced the oxygen sensors in both vehicles, even though the vehicles were new and the oxygen sensors did not need replacement. Both vehicles use computer-controlled electronic ignition timing designed to meet emission standards and deliver optimum fuel economy and performance, preventing us from advancing the engine timing. In more than 1,800 miles of driving, our tests showed no overall mileage improvements. In addition to the cost of the Platinum Gas Saver, consumers would have to pay for the oxygen sensors in each vehicle—about $140 for our vehicles—plus a labor charge for the work.
The bottom line: The best way to get the best mileage from a tank of gas is to follow the vehicle manufacturer's service schedule and fine-tune your driving habits. To learn more about saving fuel, see our guide to fuel economy.