Maybe you got a dose of dirty fuel. Maybe the filters need changing.
Had the Airflow Mass Meter go on my 2000 VW Golf but the symptoms were a little different. It wouldn't accelerate beyond 80km/h and could become very sluggish if forced. Replaced it and all was fine for a bit but then the problem returned. Looked it up on a US VW owners-club website and it transpired that a similar problem can occur if the wiring loom has been messed about with. Apparently this can commonly occur if, for example, the car has been used for towing and an extra circuit has been added for the trailer lights. The site advised looking at the wiring behind the rear lights. I did this and discovered a modification (my car was formerly a German driving school vehicle and the 'add-on' was for the drinving school light on the roof) which I removed and no problems since. That was 3 years ago.
It seems that the ECU, in such instances, detects a 'fault' in the electrics and switchs over to 'limp-home-mode'.
This appears to be a more common fault with the Bosch AFMM.
Has your car been used for towing, e.g a caravan and is the AFMM a Bosch?