Higher prices at the pump may have you thinking its time to trade down. After all, its proven most cars will require less unleaded than the larger SUVs weve all added to our super-sized lives.But one organization thats well respected in the auto industry is advising those ready to post the for sale signs to stay behind the wheel, at least for now. Nancy Williamson has had enough. Shes selling her sons red Blazer. Seems Zacharys trips back and forth from Evansville to Indianapolis are as much a drain on their earnings as their gas tank. At 4-bucks a gallon, he needs cheaper transportation to get to school. Just to drive around town its not that bad but when youre driving long miles back and forth to school it eats away at your wallet. Kelley Blue Book is where a lot of us looking to buy or sell a car go to find the prices we should ask or be willing to pay. Kelly is telling those who surf its site to hold onto that SUV to ride out the wave of high gas prices. They say what youll loose in your selling price will be more than the extra cash it takes to fill the tank. But Williamson and others may not be patient enough to play that waiting game.