How many days do i have to take a car back to dealer in New York state if you do want the car?

Unless the sales contract states you a Right of Rescission, once the contract is signed by you and the dealer, it is binding. A right of rescission in a contract gives you a cooling-off period where you can walk away from the deal. It's normal for homeowners to have this right when they use home equity loans to tap the equity in their homes, but isn't standard fare on the purchase agreement for a automobile.