Consumer Reports: Don’t fall for the Fuel Doctor FD-47

The Fuel Doctor FD-47 is a small device that plugs into a car’s 12-volt power outlet and promises to reduce emissions while increasing a vehicle’s fuel efficiency. It claims to be able to boost fuel efficiency by as much as 25 percent through what the manufacturers refer to as “power conditioning of the vehicle’s electrical systems.”

Consumer Reports tested these claims using two samples of the Fuel Doctor on a variety of vehicles, including those with four-cylinder engines, those with standard turbocharged V6 engines and cars with V8 engines. It also tested some older cars, as the manufacturer of the gadget claim it gets the best results on such vehicles.

After running the device through the organization’s standard series of tests, Consumer Reports did not find any improvements in fuel efficiency.

Drivers who are looking to save money at the pump may be advised to steer clear of devices that promise to turn a clunker into a hybrid or otherwise sound too good to be true. There are many affordable vehicles currently on the market which get excellent fuel efficiency, and it may be better to obtain a car loan to finance the purchase of a new, fuel-efficient vehicle than to spend money on a quick-fix device of questionable effectiveness.