The Internet is teeming with quick and easy ways to get more mileage out of your car. But mechanics and watchdogs urge caution for drivers across the country forced to fill ‘er up despite those rising prices: The actual results are not only dubious, but may even end up hurting your car.

“There’s a lot of black science out there,” said Bill Moss, a lifelong mechanic and director of the mechanics division at the Automotive Service Association.

“Americans are ripe for anything that will improve their fuel economy. There are a ton of charlatans in our industry,” Moss told

If the goal is getting the most miles out of a single gallon of gas -- the heart of fuel economy -- there are a number of technologies offering a better way there. They range from tiny pills you can pop into your tank to reprogramming the computer in your car.

But mechanics warn the big savings you’ll gain from any of them will be marginal at best, negligible at worst.

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Fuel Additives. Envirotabs promises a longer engine life, a reduction in harmful emissions and better gas mileage, all with the use of simple gas-tank tablets. They range from $30 for a starter kit to $512 for a package with 8,100 100-gram tablet.

Although they offer a money-back guarantee after 60 days, company representatives did not return a request for comment.

Mechanics say one should be skeptical of this apparent one-size-fits-all solution.

“As far as Envirotabs and any other ‘magic in a bottle,’ they simply are not supported by science,” said Pete Rudloff, who runs Pete’s Garage in Newark, Del., and coordinates the Delaware Training Group, which encourages on-going education and training among auto technicians.

“The auto manufacturers put a lot of money in engineering optimum performance and emissions with realistic fuel mileage, and they know how much their target buyer values fuel economy. If there were a magic solution that only required dropping a few pellets in the fuel tank they would be all over it,” he told

Additives can produce build-up that can have a harmful effect on gas lines, catalytic converters and engines, many experts say. While putting fuel cleaners and injectors into the tank are fine -- periodically or when necessary -- they won’t enhance mileage, only make the car do what it was built to do.

The federal government weighed in on pill popping and other Internet sensations last year -- including MPG-CAPS (which claim to “treat” the combustion chamber) and a $90 magnet that one attached to the fuel line to improve mileage -- after testing some 100 products for their claims of improving fuel efficiency.

“We have yet to find any device or additive that can produce that kind of result,” said Joni Lupovitz, of the Federal Trade Commission, at the time.

Handheld computer programmers. Often used by real gear heads and sports car tinkerers to enhance horsepower and acceleration, these small devices can be used to tweak your car’s central computer to get better miles to the gallon. The programmers are sold all over the net, starting at the low end of $200 a pop.

“Save on Fuel Costs & Help Save the Environment!” touts one advertisement for the SCT/Ford Economizer. A tech-support representative who chatted with said diesel owners could see a 2 to 3 mile increase in MPG, while gas drivers would see perhaps a 1 to 2 mile increase when using the device.

As always, there’s more than meets the eye, Moss said. While he acknowledges that cars can be reprogrammed (and not all can) to achieve a slight increase in fuel economy, there are downsides -- mainly, that one might have to give up a little horsepower in exchange.

"It's ‘magic in a bottle,’ simply not supported by science.”

- Pete Rudloff, owner, Pete’s Garage in Newark, Del.

“Typically the first thing to go would be the power,” he said. So basically, you’re offsetting.

“There are a lot of ways to modify your car but when there is something that results in a desirable characteristic, there is always an equal, opposite reaction,” said Moss, who works at Ferris EuroService Automotive in Warrenton, Va. Final verdict: Probably not worth the trouble.

Computer Control Module. Another variation on reprogramming the car’s onboard computer claims to give it enhanced performance. In this case, a tiny device is affixed to the computer to give it tailor-made instructions. Again, it’s mostly used by a niche group of car owners to increase horsepower, but it can also be used to modify fuel economy.

Rudloff insists that reprogramming throws off a careful balance between power, emissions and fuel economy built into the car by the manufacturer. The 1 or 2 more MPG gained by adding a module will come at “the expense of poor vehicle emissions” and power.

“Basically you can trade a little fuel economy for polluting the air you are breathing,” he charged.

Others acknowledge that the cost of these computer products far exceed any savings you will achieve at the pump.

So when it comes down to it, there are no magic bullets and no power pills -- aside from eliminating one’s need to drive altogether or going out and purchasing a hybrid or diesel engine vehicle (which for some commuters, could save quite a bit over time, say mechanics).

But some common sense tactics are still the best bet overall.

According to the Consumer Federation of America, consumers can do a number of things to improve gas mileage by as much as 13 percent. Keep your air filter clean, maintain the right tire pressure and alignment, avoid idling too much, and get rid of extra weight on the car.

And drive right, too: Don’t speed or ride the brakes, and try not to accelerate or slow down too abruptly.

“I always tell my customers that their money is best utilized by keeping their car in tip top shape,” Rudloff told “Not wasting it on gizmos that have no scientific foundation.”