tire psi question, need help on recommended tire PSI

Somewhere on the side of the tire, it will say what to inflate it to. Something along the line of "xx max psi cold"

The tire pressure on the tire itself is the max pressure the tire is designed to handle. The 96 and the 100 rating is for tire wear, the higher the number the better. The XL is extra load, meaning the tire has more belts or plys and can handle a heavier load. The sticker on the door jamb is what you should use. All manufacturers calculate the optimum tire pressure based on weight of the vehicle and tire width. As long as you stay with the same width tire then use the manufacturers recommended tire pressure. Now you can play with the pressures a little to improve traction or mileage, but don't go more than 2 or 3 psi away from what ford recommends. Beyond that you start to increase uneven tire wear.