VAG-Com: Reduce Fuel Injection in Cologne Area.

Hi.
I'm looking to reduce the fuel injection amount on an Audi 80 TDI, manufactured in January 1993 (engine code 1Z, 90PS), in order to possibly eliminate the slight jerking at the RPM range of 1300 - 1400 RPM. I live in Engelskirchen, in the Upper Bergish region, and work in Cologne, so I'm looking for someone in this area who can perform this adjustment with me. Of course, that person doesn't have to come to me; I'm willing to travel. I don't have a VAGCOM or any cables...

Thank you very much, and Happy New Year!
Hermann.