Brake pedal noise

I have a 96 jimmy v6 4wd and all of a sudden now when i push the brake pedal i can hear what sounds like air leaking or something when the pedal is held down when i let go i hear nothing also when i come to a stop sometimes the truck seems like it wants to die when holding the brake and when i take of it sometimes seems to bog out or something for a second anyone have any idea what it might be?

I have a 96 jimmy v6 4wd and all of a sudden now when i push the brake pedal i can hear what sounds like air leaking or something when the pedal is held down when i let go i hear nothing also when i come to a stop sometimes the truck seems like it wants to die when holding the brake and when i take of it sometimes seems to bog out or something for a second anyone have any idea what it might be?

Check brake booster and all vacuum lines and check valves for vacuum leaks.
MT