Idle problems - 1989 80 Quattro

["Takis Dacey" <tdacey@erols.com>]

My 80 Quattro will not idle properly. It usually starts ok but as it worms
up, the idle becomes worst. The car is idling high or it dies on me.
Acceleration is smooth and it cruises nice.
I have installed new spark plugs, distributor cap & brush, sparkplug wires,
O2 sensor. I have added the fuel additives for cleaning the fuel injectors.
Changed the fuel filter last summer. I still have the same problem.
Has anyone had a similar experience with an 1989 80 Quattro, or an Audi with
the
5cyl., 2.3 ltr. engine ?
Thanks in advance,
Takis :)