Adjusting door on a 62 C10

[forestb]

I have been noticing that when I go over bumps in my 62 C10 my passenger side door is making knocking noises. I have all new seals and hing pins and the door shuts fine and the gaps are all fine. When I try to wiggle the door by the outside handle it does not move up and down but rather I in and out a little and makes the same noise. I was wondering what is the best way to fix this. Should I try to move the rounded wedge shaped pat that is connected to the door jamb with 2 screws or should I try to adjust the striker plate?