Today I had a 9.5 hour trip from South Bavaria to Cologne, about 760 km.
After one hour the car began to stutter it was no abrupt stuttering therefore I think it was no misfiring. It felt like lifting the accelerator but you keep it constant. It was clearest at constant throttle and moderate revs. A soft stutter. Twice at full throttle and 6000 rpm the power was completely gone.
It worried me on the highway because I was in the middle of trucks in heavy traffic but finally she brought us home.
But if you briefly touch the accelerator pedal during this failure there is full reaction again. That's why I don't think it's the fuel supply.

It could perhaps be the throttle valve motor according to my first guess. I still have a second TB and will exchange it and report if it helps.
Theoretically also the voltage supply of the TB by the ECU could come into question.
Has anyone experienced such a phenomenon with a Sigma 1.6 with wired TB?

'14 4/4 graphite grey