I also am sorry for lack of terminology. Where the door latches to the actual truck that mechanism in the door has three screws I think it's coming from there I've attached a picture. I can get the door to do this same rattle when the stereo is loud with emphasis on bass with the door open. When...
Have you found out what this is, I have the same thing. I think I've narrowed it to the door actuator, the clamping mechanism that holds the door closed.