OK I see what you are saying now.... They can sometimes get "stuck" if the throttle plate is allowed to fully close and jam up against the inside walls of the throttle body. If this is the case the you will need to adjust the throttle stop screw to keep it from closing completely, or clean any carbon/dirt ring out out of the throttle body.
If it is not the throttle plate sticking than it could be the cable is sticking. If this is the problem then you will have to look for any possible kinks in the cable or try to oil it internally.
Easy way to check this is to start the car and pop your hood. Try to move the throttle with your hand without using the cable. if you can feel the plate sticking than it is the cause of your issue. Look down inside and see if there might be some build up or if the plate is jamming up against the body.
Clean the throttle body. Water and a rag or your favorite spray cleaner. Doesn't really matter so long as the gunk is gone.
Take it for a drive and see if it's better.
Loosen the 2 bolts holding the throttle plate in place and back the throttle stop out so it's not touching. Open and close the throttle a couple times. When it goes back to the closed position look at the plate and make sure it's against the bore. You can give it a little force to close more or try to move the blade. If tight, tighten the bolts and move the stop screw so it just touches the lever.
Remove the battery cables and let the car think about what it's done to you for 15 minutes or so.
Put em back on and go for a drive.