SEATTLE - With gas prices still on the rise, many drivers are turning to products that promise better gas mileage.

We tested a device called Tornado Air Management System. It retails for $70 and promises more mileage and more power.

The claims on the box promise an average of 1 to 2 more miles per gallon. A chart on the back shows mileage increases as much as 28 percent.

The stainless steel device resembles an oversized fruit slicer. There are similar brands on the market that make similar claims.

The device fits inside the air intake hose and is supposed to swirl the air into your engine, mixing air and fuel for a more efficient burn, and therefore better mileage.

I took three Tornados to AAA in Seattle, where technician Dave Armstrong and his team agreed to install them in their trucks.

Installation was easy: Disconnect the air intake hose, insert the Tornado snuggly inside the hose, then reconnect the hose. That's it.

AAA's service fleet is on a computerized vehicle analysis system that tracks everything, including mileage.

Here's the mileage before the Tornado:

14.74 miles a gallon for truck number 22.
10.25 mpg for Truck 28
11.94 mpg for Truck 31

Dave said the same people who have driven the trucks in the past will be driving them during our test.

"The same people and the same driving conditions," he said. They agreed to test the Tornado for one month.

The techs at AAA are no strangers to products with gas saving claims. They've tested magnets -- they don't work. They've tested additives -- they don't work either.

But the claims keep coming.

"That's why these places are in business, people are always tempted to try them," Armstrong said.

The Results Are In

After one month, we returned to check the Vehicle Analysis Report.

"No noticeable effect whatsoever," reported Armstrong.

When we started the test, Truck 22 was getting 14.74 miles per gallon.

"During our test period, it ended up for one month the test period was 14.68. That's negligible, yeah roughly unchanged," Armstrong said.

Truck 28 went from 10.25 to 10.20 miles per gallon. And Truck 31 went from 11.94 mpg to 11.80.

"I paid good money for those things, what did they do? At this point I would say not a thing," Armstrong said.

A Simple Way To Get Better Gas Mileage

According to experts, including the Environmental Protection Agency, no product has been proven to increase mileage.

"It's all driving habits," said Dave. "Maintenance on the vehicle is number one -- also tire pressure."

Tire pressure is something that could increase mileage right now for as many has half the cars on the road. In fact, it's not uncommon for a car to lose 2 to 3 miles a gallon because of under-inflated tires.

"The lower your tire pressure is the more rolling resistance you have and the poorer gas mileage you'll get," Dave explained.

So just for fun, I asked college student Leanne Jungquist to help us test that theory. She tracks her mileage, but didn't know the first thing about proper tire pressure.

Dave gave her a lesson, showing her where to find the recommended pressure for her tires, how to use a tire pressure gauge, and how to inflate and deflate her tires.

She discovered one of the tires on her SUV was down by a couple of pounds.

Prior to learning about tire pressure, Leanne had been keeping track of her mileage for two tanks of gasoline.

"It's between 15 and 15.5 (mpg)," she said.

After inflating her low tire she drove for two more tanks of gas. Two weeks later, the results were a surprise for all of us.

"Well, I just honestly didn't think that it would do that much because it was just one tire," said Leanne. "But it went from 15 and a half miles per gallon to 17!"

Leanne says she drove under the same conditions and did not alter her driving habits.

"I wouldn't even know how to change my driving!" she exclaimed. "I just drove!"

That's an increase of more than a mile per gallon for the price of a simple tire gauge you can get for a couple of bucks.

If you want better mileage, tune your engine, watch your driving and check your tire pressure once a month.

Energy experts say poor maintenance and aggressive driving can cut your mileage by 40 percent. But don't waste your money on gadgets. Save the cash and put it in your tank.

Other organizations that tested the "Tornado" had similar results, including Consumer Reports. But the president of "Tornado Air Management Systems" insists the effectiveness of his product has been documented by multiple automotive experts as the one gas saving device that does work.

He cites customers, radio hosts and police department fleets that say the Tornado device saved several miles per gallon.

President Jay Kim points to other TV news tests that found positive results and says he has thousands of happy customers.

"We've been selling a lot of units," Kim said. "If my product did not work, how could I maintain a high rating with the Better Business Bureau?"

Kim says part of the problem is some industries do not want to see a gas saving device work. He claims that the EPA has never found a device that saves gas mileage, are misleading.

"The EPA has never tested my product," he said.