Replace both pins, not just the top one, set your door up with the striker plate removed! this will allow you to align your door perfectly, without a false reading from a poorly adjusted striker plate, once your happy with your gaps/swage alignment, you can then replace your striker plate, carefully adjusting, so that the door shuts with virtually no resistance, and always make adjustments with the door windows in the up position, and the tailgate open! this will make sure that air pressure is released on shutting
Thom