its probably grounding out against something, what kind of guitar is it?
Certainly something is touching something else that shouldn't be touching. Are all the wires shielded? If there is any missing shield, tape those wires.

Thin and wah ish is out of phase. Swap the hot and ground leads of the humbucker, as that is more likely to have a separate chassis ground. If both are braided 2-conductor then a magnet flip will be in order.
nice looking guitar. what brand is the humbucker? different companies have different color codes. if its a duncan then the black/green swap is correct
What kind of bridge is that btw?