You would definately want to seek the advice of a lawyer. Beyond loosing your earnest money you might be liable for other expenses the seller might incur due to your breech of contract.

tell us the juicy details. please. Assuming there's a financing contingency in your contract, you could just ring up your credit cards and buy a new car, and the lender would probably rescind it's loan... kind of a mean thing to do, though. Maybe you can just give up your earnest money and walk away, ask your lawyer. I would say the seller has earned your earnest money, but again I don't know all the details.