String Buzzing?

Good description. So we know it's not the nut. The problem lies on the stretch of G-string between the 2nd or 3rd fret and the string's take-off point, where it starts to vibrate or oscillate, which is at the T-O-M bridge, specifically the 3rd saddle. You have already found the problem at the 3rd fret, but DO verify that the fret itself has not popped up for any reason. Troubleshooting also includes looking at the neck bow, and seeing that it is not negative, or humped - happens in hot places. See that there is an adequate positive bow or a slight dip (downward arch) in the middle of the fretboard.

If that's okay, then look at the saddle itself and ascertain that the string is not sitting too low in a worn groove. That can happen from wear by tuning up and down especially on an optional wound string which has the friction of sandpaper on the saddle block or from frequent bending or vibrato fretting which is how you want to play one of these babies I think?

If the saddle is at fault, replace it. However hardware is gold and a single saddle may be hard to find. Or you can buy a set of saddles at Stew Mac for $7 or a "Nashville" bridge, which is a knock-off tune-o-matic without patent or name infringement. Except they have unslotted saddles and require filing. I wouldn't want the hassle, and would buy ready-slotted Gibson or Gotoh, as I have done, the price is the price, whatever, and I recommend and have used 2 of these: http://www.stewmac.com/shop/Bridges,_tailpieces/Electric_guitar,_Tune-o-matic_bridges/Schaller_Roller_Bridge.html?tab=Pictures#details with six rollers.

Here's a pic of what you have, and may be looking at already, see the options below.

In summary, you might need to relieve the tension on your truss rod slightly, replace saddle or bridge, or turn the thumbscrew counter-clockwise on the treble side of your T-O-M, as quick fix, no money spent; gets higher action.

Find a straight edge of some sort that covers 3 frets, and make sure you don't have a high spot on your 3rd fret.
If you span it across 3 frets (in this case 2,3,4), it should sit flat, and not "high-center" on the middle fret of the 3 you are testing.

Thank you very much, that's a great help. I will promptly take a look at this and let yall know how it comes out. :D

Find a straight edge of some sort that covers 3 frets, and make sure you don't have a high spot on your 3rd fret.
If you span it across 3 frets (in this case 2,3,4), it should sit flat, and not "high-center" on the middle fret of the 3 you are testing.

Exactly.

Then put the same straight edge on the 1, 2, and 3 frets in the same point, and it should also sit flat, touching all three frets. The other poster is right- a high spot on the third fret is the most probably thing- but also make sure there's no low spot on the second fret.

Best,
Ande

Hey all! I checked the frets, there are no proud ones. So I slapped a new set of strings and had the same problem. I raised the action a little bit and adjusted the truss rod to put a tiny bow in the neck and that solved the problem. :D The best thing is, the action is still great! Thanks for the help, yall.

-A VERY happy Preacher

I'm glad you have fixed it. Play on! :D