Zap the PRAM, rebuild the desktop, and trash the preferences.
Oh, wait, this isn't 1994, and it's not a Mac.
Maybe take a look inside, see if any metal (jacks for instance) is making contact with any other metal, causing grounding issues.
Perhaps the jacks have grown a little corrosion. Try exercising the jacks.
Have you purchased a new phone recently? Installed a new wireless network, or become subjected to any new EM interference lately?
( this can be tested by bringing the pedal somewhere else to see if symptoms persist).
If this pedal has a chip pressed into a socket, try reseating the chip.
Exercising the engage switch may offer some relief.
Under warranty? Get it replaced.
Best of luck sussing this out.