AUDI 5000S Quattro engine light stays on loses power.

[smazza@mail01.mitre.org (Salvatore Mazza)]

Hi Folks I am wondering if anybody can shed some light for me.
I bought a 1988 Audi 5000s Quattro about a year ago for $300.00 could not
pass up. It needed some work but its an awesome car well worth it.
Anyways I have had this problem from begining.
The engine light comes on and the car loses power still runs but lack of
nads..
I have changed Coil/spark plugs/Fuel pump/Pressure Regulator on fuel
distributor/Oxygen Sensor/Temp sensors.
I have lost hope.
And I Refuse to bring it to an AUDI service center..will not pay crazy
prices.
I do 90% of my own work.
This is my 5th AUDI so I know most problems.

Please help..
thanks
smazza@mitre.org