2010 gmc crew cab, check brakes light

[2010GMCSierra]

So I Received a Check Brakes Light, I checked the brakes and put new pads on the front, when I brought it to GM, They said the code was a vacuum problem, so I checked for leaks and sprayed around the booster with carb clean and no engine idle change, if i try and hold the brake pedal and rev it up the pedal comes off the floor and the truck lunges forward, basically like it wont hold the front brakes it just pushes them, has anybody experienced this problem?