Using emg-81 pickups, when volume is up I get excessive scratching from top string when moving from one fret to next on low E string.

When I turn down the fret, I don't get the sustain I want

My question:-
- should I just adjust volume knob and exchange sustain.
- Is this a technique thing, should I go back to drawing board and learn how not to make this noise.
- Any other advice would be great