I'm trying to fix an issue on a (somewhat cheap) newer bike and it's giving me a bit of a run around. The issue is that when shifting up and down, the alignment is off. Normally, I could easily fix this by changing the tension of the cable, checking my limiter screws, making sure nothing is bent or out of alignment- but it's not quite worked in this case because the issue appears to be in two directions at once. Simply put, after getting the tension as close as I can– the gear is hesitant to switch from the 3rd to 4th gear when going down, but it's ALSO hesitant to shift from 4th to 3rd while going up.
I got suspicious that the tension itself might not be the problem, so I made a small mark on the cable right near the housing, and checked it going up and down again. Sure enough, in one direction the mark is about 2mm (1/16"ish) when shifting one way on 4th gear, but it's nearly covered going the other on 4th gear again.
Would this be an issue up inside the gear shifter itself then? The cord itself isn't frayed or seeming to rub inside the housing.