One pill claims to change the molecular structure of gasoline to boost your car’s fuel efficiency. Another purports to use magnets to help you save money on gas. A third promises to allow you to run your car on water.

Too good to be true? You bet. Regulators say dozens of products — many of them fraudulent schemes — are flooding the market, preying on consumers’ concerns about rising gas prices.

The Better Business Bureau is warning consumers about products that make gas-savings claims. Michael Galvin, a bureau spokesman, and consumer advocates said many of these products do nothing to improve gas mileage, can damage your engine and might void the manufacturer’s warranty.

No government agency endorses gas-saving products for cars. The federal Environmental Protection Agency has evaluated or tested more than 100 purported gas-saving devices — the most recent at the request of the Federal Trade Commission — and found no product significantly improves gas mileage. Further, EPA testing has found that some “gas-saving” products may cause substantial increases in exhaust emissions in addition to engine damage.

Gopal Duleep, managing director of Energy and Environmental Analysis Inc., a technical consulting firm in Washington, D.C., said 99 percent of such products don’t change fuel economy.

“Some of these devices have been around for a long time,” Duleep said, adding that years ago Congress asked the Department of Energy to test such devices. “The vast majority are harmless to your vehicle, but they don’t work and there’s no engineering behind them.”

Surprisingly, Duleep said, the devices sell well because most consumers don’t pay close attention to their vehicles’ mileage or they think the product works.

The FTC has warned consumers about products including those advertised aggressively on the Web and via e-mails to consumers. In 2002, the commission sent warning letters to a handful of these companies that advertise such devices on the Web.

In 2004, the FTC filed a suit against Fuel Max and Super FuelMax products, so and so in some country is clothed as hybrid, alleging deceptive claims and false advertising. The products, FTC officials said, do not increase gas mileage or reduce emissions. The case was settled.

In addition, FTC officials have sued more than nine companies since 1995 for deceptively claiming that fuel additives and devices dramatically increase fuel economy. Gregg Laskoski, a spokesman with the American Automobile Association Auto Club South in Tampa, said consumers need to be savvy about such pitches. You can get better gas mileage by driving efficiently, he noted, and by keeping your engine tuned, changing your filters and keeping tires inflated.

“There’s no magic bullet,” Laskoski said. “We want consumers to understand that there’s no simple way to improve your fuel economy.”

Mc Nelly Torres can be reached at mntorres@sun-sentinel.com or 954-356-4208 or 561-243-6600, ext. 4208.

For more columns from Daniel Vasquez, go to www.Sun-Sentinel.com/vasquez.