Revs sticking at 2000 at idle

[bengim]

Guys, i had a quick search and couldn't find an answer so i thought i'd start a new topic.  Recentl my G has started to stick at 2000 revs when idling its a bit intermitent and seems to be worse when the engines been running a while.  Is this a familiar problem, does anyone know what it might be?  my local garage cleaned the throttle body as they thought that might cure it.