Buying a car with a credit card is a special case. Car dealers don't want to swallow the substantial fees, but even more important, they cannot risk returns under the Fair Credit Billing Act. If you charge your new car and return it, the dealer may have to take it back. If they refuse, you may be able to get the charge reversed. This is a BIG problem. Most dealers will allow you to charge a piece of the purchase price, but not most of it.
Bruce