WINTER PARK, Fla. -- Does your car get the gas mileage advertised? Probably not. Even the Environmental Protection Agency admits it probably doesn't.

Reporter Michelle Meredith has been testing cars and their gas mileage all week. She tested five popular cars to see how they fared when she drove them on the streets of Orlando.

Pain at the pump has drivers wanting to know which cars get the best gas mileage.

"How accurate are the miles per gallon on the sticker that comes with our cars?" Meredith asked AAA's O.S. Brannon.

"Not very accurate. Not at all. In fact, we find that over 90 percent of them are not accurate," Brannon said.

Ninety percent? How is that possible? The current mpg test was developed more than 30 years ago, and it's about as un-real world as it gets.

"And if they think they are going to get 30, 35 (mpg) and in reality, they're going to get 20," said David Champion, of Consumer Reports. "I think that is a great disservice to the consumer, and in some ways, actually cheating them."

So, the I-Team went in search of the truth. Meredith got five popular cars off the lot at Jim Lash Blue Book Cars in Sanford -- a 2002 Nissan Altima; a 2005 Camry LE; a 2002 Ford Mustang; a 2003 Jeep Grand Cherokee and a 2005 Chrysler Town and Country.

Blue Book mechanics made sure they were tuned up, the air filters were clean and the tire pressure was perfect. Then we gassed them up and hit the road.

Our goal? To compare the mileage we get to the mileage carmakers claim they get.

We did two loops through Central Florida, covering just over 50 miles. We made our way through College Park, downtown Orlando, Casselberry and then back to the Winter Park area.

"(These are) real world conditions. We're caught in traffic. The AC is running high. (These are) real world conditions. I think we're going to be substantially lower," Brannon said.

The results? Two cars -- the Mustang and the Camry -- did get lower mileage. The Camry was supposed to get 24 mpg in the city. We only got 17.5

But three vehicles -- the Altima, Grand Cherokee and the Town and Country -- actually did better than the government's sticker. For example, Chrysler says their Town and Country gets 19 in the city. We squeezed out over 23 mpg.

What we learned, experts say, is a lesson for all of us -- how you drive really matters.

"You can make probably 50 percent difference in your gas mileage just by how you drive," Champion said.

Top 10 Ways To Drive More Efficiently

The WESH 2 I-Team discovered the top 10 ways you can drive your car more efficiently:

1. Nice and easy saves gas. Herky jerky does not.
2. Don't waste fuel. After you fill up, make sure the gas cap clicks three times. Every year, Americans let 147 million gallons of fuel vaporize into thin air.
3. Gas up during the coolest part of the day. You get more liquid because the gas is more dense.
4. Remove bike racks or cargo carriers from the roof. Roof carriers can cut your mileage by 10 percent.
5. Empty your trunk of everything but the spare tire.
6. Keep tires properly inflated to avoid rolling resistance. "As your tire is rolling, it's grabbing more ground because it's deflated. What's happening to your gas? You're using more energy from the engine to get the tire rolling and you're using more gas," said Consumer Report's Jennifer Stockburger.
7. Roll up your windows, especially at high speeds. The wind resistance can hurt your mileage as much as the air conditioner.
8. Use cruise control and drive the speed limit. That can save you as much as 11 percent.
9. Turn off the car when picking up the kids. Starting the car uses less gas than idling.
10. Plan your day efficiently so you make less trips. Less trips equals less gas and more money in your pocketbook.

To comment on this story, send an e-mail to Michelle Meredith.