Rick, have you checked your neck relief and action height? First, though, push down hard on the G-string on both sides of the nut to make sure the string is seated all the way down into its nut slot.
I took out one of my Taylor GS Minis the other day to try and get back to playing. Two bad hands and a bad right shoulder, but I'm determined to play a few tunes. I noticed that the G string sounds dead. That's the only way I can describe it. So I changed to a new fresh set of strings and it still sounds dead. Strum a chord and when you hit that string, you can hear it. Almost just a "clump". The other strings sound just fine. Any idea what I could be dealing with? Thanks for any suggestions.