Don’t be surprised if window stickers show ’08 models get worse gas mileage than you expected.

For the first time since the mid-80s, the Environmental Protection Agency has revised the test it uses to measure city and highway fuel consumption, hoping to provide a more accurate estimate of what you’ll get in real-life driving.

That means the EPA is testing new cars and trucks at higher speeds, with harder acceleration and the air conditioning on for part of the time. As a result, ’08 mileage estimates are down 10% to 25% from comparable ’07 models.

The largest declines are for cars with four-cylinder engines and hybrid powertrains, which must worker harder than larger engines when the AC is on and during quick accelerations.

The new test reduced the city mileage for a typical compact by 4 m.p.g., and by 10 m.p.g. for some hybrids. Models with V6 and V8 engines only lost 1 or 2 m.p.g.

September 6

Interest.com’s latest survey of lenders found the average cost of a:

• Five-year new-car loan dipped to 7.71% from 7.77%, after holding there for three weeks. It is well below the 7.93% we were paying last September, and the 8.06% we paid two years ago.
• Four-year new-car loan fell to 7.66% from 7.72%. But it is up from 7.64% -- a recent low hit only three months ago. Today's rate is lower than the 7.87% we were paying a year ago, and a lot less than the 8.01% those loans cost in September 2005.
• Three-year new-car loan followed suit, easing to 7.59% from 7.65%. Today's rate is almost a fifth-point less than the 7.87% we were paying last September, but almost one-third of a point lower than the 7.98% we shelled out in September 2005.
• Three-year used-car loan also fell, coming in at 8.43% after holding at 8.51% for three weeks. It is close to the 8.44% we paid just two months ago. It costs a lot less than the 8.83% we paid last September, and it is more than one-quarter-point lower than the 8.77% of two years ago.

August 29

Over the next several years, Nissan will become the first automaker to equip every car and truck it makes with a gauge that tells drivers how much gas they're using.

The fuel-efficiency meter will appear as a horizontal bar on the instrument panel.

When coasting downhill, the bar is long and orange, an indication that the car is getting good mileage. During hard acceleration the bar becomes much shorter, encouraging drivers to ease up on the gas.

Nissan says drivers who use the meter to maximize their mileage will save about 10% at the pump.

August 8

An open top can turn the most mundane trip into a joy-filled jaunt, and you don't have to spend a fortune to enjoy it.

Our favorite convertibles -- the Mazda MX-5 Miata, Mini Cooper and Ford Mustang -- all cost less than $26,000.

They deliver a pleasant ride, enough room for a couple of suitcases even with the top stowed and plenty of power, even though we recommend the smallest engines to save on gas and hold down the price.

Click here to learn more about the best convertibles.

August 7

Before buying a new car or truck you've got to know:

• How much the dealership paid for the car you want.
• How much other buyers are paying for similar models.
• Whether any discounts such as rebates or cheap financing are available.
• What auto loans cost, including interest rates and fees.

Buyers without that information will pay thousands more than they should. Almost guaranteed.

Interest.com’s 6 step plan to get the best price and cheapest loan tells buyer's how to find and use that information to their advantage.

July 25

Extended warranties aren't warranties so much as insurance policies complete with deductibles and other insurance-like rules.

They're big profit-makers for dealerships, so don't be surprised if your salesman pushes 100,000-mile "bumper-to-bumper" protection very hard.

But extended warranties are rarely worth the extra cost.

That's especially true if your new car or truck already comes with one of the great 60,000- or 100,000-mile powertrain warranties that many makes are offering on 2007 and 2008 models.

While they don’t cover some major components such as air conditioners, cooling systems and electronics, they do cover engines and transmissions -- the most costly parts to fix.

Click here to learn more about all the longer factory warranties, with extras like roadside assistance, being offered on new cars and trucks.

July 23

The typical consumer who's missed one or more car payments has a credit score that's 98 points lower than someone who's made every payment on time.

A new study by Experian, one of the three major credit reporting agencies, says the average credit score for consumers with no late auto payments is 703, while the average score for consumers with at least one late payment is 605.

That pushes those car buyers into credit scoring’s worst category. Anyone with subprime credit has a difficult time obtaining loans from most banks and finance companies. They’re often forced to borrow from lenders who specialize in loans to borrowers with bad credit, with higher interest rates and more onerous terms.

If you’ve made a late auto payment, and Experian says 12% of consumers have a least one on their records, your credit has suffered. Here’s what you must do to raise your credit score.

July 17

The biggest discounts are on big trucks such as full-size pickups. But we've found some pretty good deals on small cars this month:

• The Nissan Versa, one of our favorite subcompacts, comes with 0.7% financing for 36 months up to 4.9% for 60 months, or $500 cash back. Get additional $500 cash back by financing through Nissan.
• The Ford Focus is offering $2,500 rebates or 0% financing up to 60 months and 1.9% financing for 72 months.
• The Kia Spectra has a $1,500 rebate or 2.9% financing and $1,000 bonus cash if you finance through Kia.

July 13

How much car can you afford?

The best rule-of-thumb we've seen is that monthly payments shouldn't exceed 8% of your gross monthly income. If that's $3,000, for example, then the payments should be no more than $240 a month.

Nor should you stretch your loan out over more than 48 months, or four years, to lower payments enough to fit that rule.

New cars and trucks start depreciating as soon as they're driven off the showroom floor. Stretching payments out for 60 months or more virtually guarantees buyers will be "upside-down" for much of the loan. That means they'll owe more than the vehicle is worth, making it difficult to sell or trade.

Yet extending payments over five, six or even seven years is how dealers persuade customers to spend -- and borrow -- record amounts for new cars and trucks.

According to the Federal Reserve the average length of an auto loan was 61.1 months in May and the average amount financed reached an all-time high of $27,163. At 7.8% annual interest, the average rate for such loans, the monthly payment would be a hefty $540 a month.

June 27

Whiplash is the most common injury suffered in car crashes. While neck injuries are rarely life-threatening, they can be quite painful, even debilitating.

They can also be prevented if the seat and headrest are designed to support the head and keep it moving forward at the same speed as the rest of the body when a car is struck from behind and lurches forward.

Yet only 22 of 75 cars and trucks tested by the Insurance Institute for Highway Safety provided good protection from such injuries when rear-ended at 20 m.p.h.

The headrests in such popular cars as the Toyota Corolla, Buick Lacrosse, Pontiac Grand Prix and Cadillac CTS did a particularly poor job in preventing neck injuries.

Take the Institute's test results into account when you buy a new car or truck -- especially if your neck has already been injured in a wreck.

Have a question about cars or your finances? Ask us at editors@interest.com