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Common gas-saving myths, misconceptions

March 7, 2011 12:00:00 AM PST
The Automobile Club of Southern California has been testing cars nearly since the first ones hit the road, so they've heard about all the tricks to saving gas.

What they have found is that a lot of them just don't work. For example, keeping the engine running instead of starting, stopping and starting again.

"Our rule of thumb is, if you're going to have the engine off for more than two minutes, turn it off," said Jeff Spring of AAA. "You can save gas doing that. But if you're going to just idle for a little bit, for less than two minutes, it doesn't matter."

How about changing the air filter?

"The air filter on more recent cars or on more modern cars really doesn't make a difference, because all these cars have computers on them and they adjust for the air flow and the air intake," Spring said.

And, no, premium fuel doesn't help either.

"A lot of people think that they're babying their engine and getting better gas mileage if they put premium gasoline in their engine, and that's not the case," Spring said.

Some think increasing tire pressure is a good idea. In reality, it is the opposite.

"Some people say that if you over-inflate your tires, you'll get better gas mileage" Spring said. "It's negligible and the problem is you're going to wear out your tires sooner, so you're going to incur another kind of cost, and it can be very dangerous."

And finally, how about all those fancy fuel-saving devices and additives? Forget them.

"In 30 years of doing testing, both the Auto Club and for however long the federal government has been testing these products, we haven't found one that works," Spring said.

What does work is just calm driving on the highway, no zipping in and out of traffic and no jump starts from a red light.