[V8] 1992 Audi V8 4.2 running lean

[Dag Bøsterud]

I've had the transmission changed (automatic) on my 92 V8 4.2. Prior to this, 
the engine had no fault-codes using VAG-Com.

After the transmission was changed, VAG-Com reports fault code "Adaption Limit Exceeded".
At part throttle you can feel the car's running lean; a look at the spark plugs confirm this.
At full throttle, the car is fine.

The spark plugs are new (and correct), the oxygen sensor are new and the fuel pressure regulator are new.
I also checked the air mass meter, it doesn't appear to be broken. I cleaned it with carburettor cleaner.

I also tried to disconnect the oxygen sensor; the car then ran just fine.

Does anyone have any idea of what could be causing this?

/Dag Bøsterud

Norway