hihg reving auto golf 1800 cabrio 1991

I have a golf H reg automatic carbrio that has fluctulating revs and intermitantly cuts out has been to garage with no luck  revs are constantly high  any ideas would be appriciated

hi use this bloke best ?160.00 i have spent so far on my car drives like new and tick over is spot on
http://bromyardvw.com/aboutus.aspx
                 cheers paul