Pulling the codes via the rev-counter: Does anyone know what they mean ?

[thyrsted@olsy.dk (Kenn Thyrsted Nielsen)]

Hi, again.
This time i'm trying to be more specific:

I'm experiencing an periodic problem with my '87 200 tq Avant:
Recently the engine check light is coming on under light to medium acceleration.
(also under full throttle, but i only checked this once)
Slightly backing off the throttle makes the light dissapear, and i can feel the engine pulling more willingly (not much).
I pulled the codes; it said 3000rpm (MAC 06A).
I know it's odd for an '87 but the engine was made for schwitzerland '83-'87.

Now i hope that there is someone out there, who can tell me what that code means.

I'm suspecting the knock-sensor as i know the ECU would back off timing under knocking conditions, until a certain point where it will back off no further, and the engine check-light would come on.

Please correct me if i'm wrong.

TIA (and hoping)
    Kenn (still trying to understand quattros)