Hello everyone
I have a 1998 ford f150 with the 4.6. Today my drivers side windshield wiper decided that is only want to go up half way or get stick at the very top. I can also move the windshield wiper by hand very easily. The passenger side one still works great. Just wondering if anyone new what the issue was

 

Had the same issue with mine. Went to autozone bought a new windshield wiper motor and all new bushings fixed my problem and have worked great since!

 

Mine did that and all it was is the nut that holds the wiper arm was lose.

 

Check the nut.
Or the splines are stripping.
I pulled mine and wrapped a piece of aluminum foil and reinstalled the wiper. That was ten years ago.