R56 N12B16A stutters at 2500 rpm

[Gurkenfahrstuhl]

Hi,

I am working on an odd problem. Our R56 from 09 is fully ok at idle. When accelerating, at 2500rpm it falls into heavy stutter and can not increase in rpm and speed further.

Only from time to time when trying for longer time in that stutter area, a 2B15 and 2B68 are thrown. No error codes else.

Throttle flap and MAP sensor have been replaced. Also timing has been controlled and slightly adjusted.

Intake manifold and pcv have been searched for leaks, no leaks found.

All to no improvement at acceleration 2500 rpm stutter.

VVT motor worm gear looks worn. I ordered a new one.

Did you ever experience this behaviour at a Mini?

In the beginning it was possible to come into above 3000 rpm and from there on car ran nearly normal again into 6krpm. But now even that is impossible.

Any advice would help me a Lot.

Thanks,
Wolfgang

Again: Idling is really undisturbed.