Problem accelerating under WOT

[s2carlo]

Yesterday I experienced (and reproduced) an problem.
When accelerating with WOT following occurs:

- turbo pressure goes up to 1.1 bar i.s.o. 1.5 -1.6bar;
- car starts stuttering, jittering above 160-170kmh;
- car doesn't accelerate anymore (although turbopressure is up);
- car hardly reaches 200kmh.

If I then release the throttle a little:
- turbopressure drops of (a small plof is heared)
- the car stops shaking, and stuttering and accelerates again, although not as it is suposed too
- car reaches 220kmh i.s.o 260kmh that it reaches before easy;

Any ideas & good tips are appreciated

Thanks
Carlo

[s2carlo]

just putting it on top again

[A80Avant]

could be your coil packs

[nigelm]

Juddering

Loose spark plug is the optimists diagnosis.
Cheaper than coil pack failure.
Have a look.

nigelm