Hey guys, I've been having an issue with my les paul knock off. I have Guitar fetish pickups (which are really nice) in it, and redid the electronics recently to make sure they worked (the guitar is like 15 years old). It sounds killer until I get around or above the 20th fret, then the sound just dies.

I have no idea why, I hope someone here can help me. thank guys!
That's generally a problem with guitars, is that as the string length gets shortened (AKA, higher up frets), you lose sustain. Work on your vibrato, as this will help a lot. If your vibrato is perfect and the sustain is still rubbish, you may have to get the frets re-leveled IF AND ONLY IF they are of an uneven uniform height, or if there is A LOT of visible wear.
Thanks, I'll check it out when I get back home to my workshop (aka dining room table) this weekend