guitar tone muffling at random!?

ok so maybe someone can help me narrow down this problem. so i have an American deluxe fender strat and a fender blues deluxe reissue and for some reason my guitar tone will go from being crystal clear to horribly muffled and then back to clear again when i mess with the toggle switch. so idk if its the amp or the guitar, im leaning towards the guitar because why else would flipping the toggle switch fix it? im just really frustrated and dont want to believe its the guitar because its relatively new and was effing expensive. any suggestions ?