My inclination is my freehub or my front chainring is worn out.
I get in to anything higher than my 4th gear on my cassette and i crank and it just skips. I adjusted my chainline today to a perfect distance (51mm on the Scream). It shifts in to every gear nicely except my 9th (which i just said fuck it, whatever). I lubed up my chain today and all that just regular maitenance sorta stuff.
Yet still in anything above the 4th (And sometime 5th) it skips if I crank on it. It's a real pain in the ass for getting speed for stuff when I gotta pedal like a mad man just to get going.
Specs…
Front Chainring: Shimano Something, 34T Standard (bought beginning of last year)
Cassette: Shimano LX 11/34 (bought in October)
Chain: Shimano LX (edit3 weeks old)
though those might help
Peace out
Cam.