by Tanta on 5/09/2008 06:39:00 AM

Thinking about trading in that Tahoe for a Civic? Sit down.

High fuel prices are causing the value of used SUVs to plummet, often below what's listed in the buying guides many shoppers use to negotiate with dealers.

As a result, some new-car buyers think they're getting cheated by dealers who are offering them little for their SUV trade-ins.

"The dealer is going to offer a price, and the customer is going to be ticked off," says Tom Webb, chief economist for Manheim, operators of auctions where car dealers buy their used-vehicle inventories. "The guidebooks have not caught up to the market," he says.

I'm waiting for Gretchen Morgenson to get all over this anti-consumer behavior. Meanwhile,

Webb's figures show wholesale prices on big SUVs such as Chevrolet Tahoes, Ford Expeditions and Toyota Sequoias are down 17% from a year ago. Full-size pickups have fallen as much as 15%, Webb says.

"It's a challenge," says Adam Lee, president of the Lee Auto Malls dealerships in Maine. "How do you tell a good customer, 'You paid $32,000 and now it's only worth $17,000?' "

Why, you should just hire some newly-under-employed Realtors®. They've had some practice at that kind of thing lately.

AutoNation's Jackson says he thinks affluent buyers may be hanging on to their SUVs even after they buy newer, more fuel-efficient vehicles, banking on gasoline prices falling so they can sell their big SUVs later for a better price.

Better hope you can hang on to that house with the three-car garage, then, because your HOA won't let you put it up on blocks in the yard, I'm afraid.