Hello Leslie and welcome to the forum! Well, I have no personal experience with the 4-door model Ranger, but I would start with good lubrication of the door latch mechanism of ALL 4 doors. This will require removing the door panel and spraying/smearing a suitable lubricant on all moving parts and linkages. Once that is done, and before reinstalling the door panels, I would close all the doors several times and take note if they are working smoother. Also, observe if the door body lines align correctly. If not, most likely there is excessive wear in the door hinge (probably the FRONT doors as they get opened most often). Give that some thought and good luck!