Window motor bushings. It's an easy fix also. Some folks remove the entire regulator from the door to get the motor out. but you don't have to...just look at the door where the motor is, and you will see 3 dimples that line up with the motor bolts, drill these out with a 1/2" bit, and a 5/16" or 8mm socket will fit right in. With the window all the way up, there is a hole in the gear plate, place a 3/8" extension in there and it will hold the window up while you remove the motor. Unbolt the motor (3, 8mm or 5/16" bolts), reach in through the access hole, wiggle the motor a little , and it will pull right out. If you can rotate the steel gear back, and forth by hand, the bushings are bad. You can either buy these in a kit for around $15, or make your own.
Your window channels could be out of adjustment, or your rollers worn (they are square, so they don't really roll), but my bet is on the motor bushings as they will allow the window to cock, and stop in partial up, or down possitions.
Better get used to doing your own work, as our Bronc's are getting old, and tired, and require almost constant maintence. Even a rich man can go broke at the dealership.
Let us know if you need more info