brake pedal wont come all the way back to the top after being pushed.
have to pull it up with my foot. master cylinder is fine can it be the booster.

 

How's the fluid level? Losing any? Could be the booster or a small leak in one of the lines. Carefully and slowly inspect all the lines. I have a leak in all 3 of my vehicles, all around the winter time, it sucks and they are difficult to find/ notice.