1993 XLT F150. The drivers side window goes down but you have to help push up on it to get it to go up. 2 weeks later the pass. side window does the same. Any suggestions what to look for or test first? Thanks

 

I also have a '93 Flareside that had this problem. If you remove the power window motor (either side) and remove the cover for the ring gear that drives the window lever up and down, you'll probably see lots of little plastic/nylon bits (mixed up with grease).
This mess used to be 3 nylon/plastic rollers that resided in each of 3 indentations between the odd shaped whatever it's called (looks sorta like a shamrock without the stem) and the ring gear assembly. These rollers are roughly 3/8" diameter by 3/8" long and some owners have made them out of aluminum rod. I've seen some replacements on ebay but I wound up using some nylon spacers (3/8" dia by 1/2" long, ground down to 3/8" long) that I found at home depot. Put those babies in, packed the ring assembly with lots of bearing grease, closed it up, reinstalled into the door and voila!-- it works. I've got another set just waiting for the passenger side to go..........Hope this helps. I was led to this remedy via some message I ran across on the 'net.