My trusty 2012 Btwin Triban 3 is poorly. I can't get it to shift in to the big cog or the little cog on the cassette at the back without playing with the barrel adjuster in between (Shimano Sora 9sp R3000, Double chainset). Things I have tried to resolve this include:

• Checked that the wheel is seated in the frame straight.
• Used my Park Tools DAG tool to check horizontal and vertical hanger alignment.
• Replaced the inner gear cable.
• Replaced the outer gear cable near the mech. Downshifting feels very free and easy on the shifter.
• Played with limit screws.
• At my wit's end, played with B screw.

If I tension the cable such that I can get in the big cog but not the smallest, when I'm upshifting it's as if one of the upshifts just goes missing and doesn't do anything, or at least very little.

I've been eyeing up Wheeltop's new wireless road groupset for under £500, and I can't be bothered buying another Sora shifter if I'm only going to use it another 6 months.

Is my shifter dead? Is this something that can happen on Sora 9 speed shifters? There's currently a faulty one on eBay for parts that seems to have a similar issue. Cheers!