Having been a sales manager in 4 Ford dealerships since the late 80's I can assure you dealers won't like a credit purchase. many times folks would put 5K or 10K down and want to use a miles card for that reason. The problem is the fees on that much money comes right out of the car deal and the answer will be no unless you pay the credit card fees to the dealer!

With everyone knowing the dealers cost today, why would a dealer absorb the credit card fees on a short deal? Your going to beat the salesman up for an invoice deal and then want to use a credit card to pay for it? Won't happen