I suggest starting a new thread if you don't get a lot of responses. This one is 3 years old.
Check the fluid level and look for leaks around the master cylinder and each wheel. Could also be air in the system requiring a bleed. If none of that pinpoints the problem then it's probably the brake booster. Do a search - it's happened to a few folks.
Also - it's pedal and engaged. (sorry, pet peeve).