Single Wolf or Dead Note Issue

[Pluckoff]

Older Ibanez TMB100 I bought uses.

Getting a single wolf note on 12th fret G string. Tried truss rod and bridge height adjustment. Added weight to headstock in various positions. No loose or unlevelled frets. When I tap on the back of the neck near the 12th fret with my right hand while my left hand mutes all of the strings I can hear the truss rod rattle inside the neck. Not sure if this is normal or an issue that could be causing the single wolf note. Anyone else experience this?

 

[96tbird]

First, the rod shouldn’t be rattling in the neck. Tighten it a bit to snug it up in there.

 

[Pluckoff]

Tried adjusting both a a quarter turn tighter and looser..no change. Would it help to remove the neck and see if I can get to it from the mating end (base) facing the body?

I want to sell this guitar, but I want it as right as possible for a potential buyer. It's the only issue it has.