Let me give you the full timeline. About 1 month ago...everything was working fine. Then one day the passenger side door started to skip when closing, but it closed. A few more times of that and it just skips mostly and didn't close or open reliably. It deteriorated very fast.
So we disengaged the power door mechanisms and operated both doors by hand. The driver side door operates very smoothly. You can use one hand to open and close. The passenger side door was a different story. There is noticeable resistance when operating by hand, but it still closes, opens, and latches properly by hand.
So I did the easy fix and just replaced the center rollers on both sides since neither has ever been replaced just to see if that fixed the problem. In the process of doing that, I tried to slide the passenger side door while the cables were not attached and the door slid very easy...worked wonderfully. I finished reattaching the cables and putting all panels back on. Tried the power door mechanism again and still had the same problem.
The fact that the door worked beautifully without the cables attached tells me that all rollers are working fine and the door is aligned properly. The cables had no visible damage to them that I could tell.
The door still had stiff resistance when operating by hand with the cables attached and I'm fairly sure this is the reason for the skipping when the power mechanism tries to open and close the door.
All of this tells me the source of the problem is in the cabling/motor mechanism...pulley or something...who knows. This is why I'm looking for your expertise to guide me in the right direction.
That's about it. Let me know if there is any more information that you are looking for.