Will you be OK if you put 1 gallon of diesel in your car then dilute it with 13 gallons of unleaded?

Obviously I wouldn't recommend the reverse but if your car is running without any apparent problems than just run it dry and put normal gas in. The alternative would be to siphon it dry. It shouldn't do any damage. Diesel just has more carbon molecules than gasoline which may lead to a little more carbon build up on your valves. Your engine probably won't run quite as good and you may not see normal operation until you have gone through a couple of tanks.