Airbrush stuck ? HELP!!!

Something is not working or stuck in the Finger Lever Assembly. Check it by removing the airline from the airbrush. Then unscrew the valve nut. Check the spring, valve plunger and valve washer. Clean and replace as needed.

http://www.paascheairbrush.com/parts_2003/HHSAirbrushPartsList.pdf

sounds like maybe the pin mechanism that lets the air in through the hose is stuck. did that make sense? some times i can see it in my head but can' t explain it. anyway maybe u should put a little airbrush oil on it ( the moving pin part). most airbrushes operate pretty much on the same premise, but then again i don't have that model of airbrush so maybe someone else can be more specific.