This past weekend in Ohio, I had my '87 Mustang GT out, and pulled up with the left side facing the pump, as I would in my Jeep. Alas, the Mustang has the door on the right side (hadn't driven it in a while). Later the same day, I drove my '69 Mustang, which has the gas cap on the rear. Then the next day, I had to fill up my Town Car rental, which had the door on the right side also.