Not too familar with the Audi 100s, but here goes.....................
ignition coil giving a weak spark?
Coolant Temperature Sensor for the fuel injection?
How was the CO adjusted? By checking the current to the fuel pressure
I think that you have the electronic fuel pressure regulator on the side of
your Fuel Distributor.
I have changed a few FPRs for different VWs and Audis, so yours might be
catalytic converter or muffler clogged? What is the vacuum during different
engine rpm levels?
Either too much fuel, not enough spark at the right time, or not enough air.
(One out of many daves)
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