After fitting a new throttle body you need to do a "throttle body alignment" proceedure which you will need a full working VagCom diagnostic program, a good independant garage or autoelectrician should have the required equipment to do this.
Due to the age of the car it is not an OBD2 compliant it uses a VW fault code system of 4 or 5 numerical codes, but it does have a 16 pin OBD connector in the storage compartment by the fusebox, and the codes can only be read with the VagCom diagnostics a generic EOBD code reader will not work.
Was the replacement throttle body new or from a used supply? as it is a common fault you have described and can often be cured by cleaning the inside of the throttle body with a spray carb cleaner and an old tooth brush, hold the butterfly fully open and spray the cleaner into the body and scrub the inside with the tooth brush, paying close attention to the area where the butterfly valve will touch the sides of the body
nige110162(at symbol)hotmail.co.uk
nigel
September 2011