A wah sound and buzzing don't really seem to go together. I am not that far in the lessons yet, so I will offer an opinion on the buzzing. I have noticed twice recently (on two different guitars that I had some intermittent buzzing. Strangely enough they were the same issue with different causes. On one guitar the set up had to be adjusted a bit. The notch in the nut had to be slightly altered. On the other is was simply an issue with re-stringing a guitar. I guess I was just a little careless but the final, lowest winding on the string was not quite low enough so it was not putting adequate downward pressure on the nut, making it act like the first guitar. It might have been possible to fix the first one by adjusting the string but it is too late now.
But if you thing about it, if you are not careful, there is about 1/8" to 3/16" of play for where the string could leave the tuner. Pretty important stuff.