Driver Power Window

Driver passenger power window on my Jimmy judders both rising and lowering. Has anyone any ideas as to the reason or cure? Thank you very much everyone.

Grit., dirt, mud or sheep will prevent smooth movement, so a good clean is the first action ^^^^^
IF it's not the above old age can make the rubber less pliable and the flocking can wear away (causing friction), both causing window judder. The classic car fix is graphite used as a lubricant. Any old HB pencil will do, grind up the graphite and apply to the rubber channel. Oil or grease will damage the rubber, graphite doesn't.
This is an old timer car fix, along with black shoe polish for all that black plastic trim. Works better than any of the expensive alternatives.
 

Mine went in fits and starts when I first got my Jimny. I had some problems on my other car and had some rubber lubricant which worked well, I think it is silicone based. I had reason to take the door card off and applied some lithium to the mechanism and no more problems.

Usually just a good clean works.

Rob8n

Thank you everyone. Gave it a good clean;  now working perfectly!