I have a two handle Gracier Bay Kitchen faucet only four years old. Although I have changed the two washers, it still leaks. Any suggestions?

Are you also changing the seats that the washer sits on? Seats can have chips or burrs that cause them to leak and chew up new washers. Some seats can be refaced while others its better to replace.

Pull a stem and washer assembly. If the washer's chewed up then Bob's dead on. Replace the seat or reseat it. Good luck, Tom