Sorry for this..
So I've just taken a bike out of the garage that's not had much love for awhile. I'm trying to index the 9 speed XT shadow rear mech, but can't for the life of me to get it spot on. Cable seems simultaneously too tight in the larger cogs (and so won't shift down the block) and too loose in the smaller cogs (and so won't shift back up the block).
Have I missed something, or is this new cables / mech hanger alignment time?
Most likely a cable issue - contamination or corrosion. Possible mech wear, or B tension.
Big to small problems is almost certainly down to 'sticky' cables de to dirt or contamination - Release the cable clamp, run some chain lube along the inner, slide the outer back and forth to free it up. Reclamp and re-index.
Thanks, both. Will have a crack - probably new cables time...