1999 Mercury Sable LS gas/brake pedals make crackling noise when I press them. Any suggestions? Thanks?

I have a 1999 Mercury Sable LS, with the Duratech 24V engine. It has 81k miles on it. When I press the gas to take off, it makes a crackling noise in the pedal/dash area. Also sometimes when I press the brake and let go it will make the same crackling noise. Any Suggestions? Thanks