throttle body stuck open

The throttle body on my 91 mazda b2200 is stuck open. Isnt it supposed to be shut all the way when idling? its hesitating when I give it gas and sputtering at idle. I ran some carb cleaner through it but the neighbors got pissy about the noise so I had to quit. I think it cleaned up the sputtering a bit though. but I still have no idea why that throttle body is open.