Jerking XM v6 12v with stickshift

[PhilCrown]

Greetings from the Netherlands everyone!

My name is Phil and I was wondering if anyone has experienced the following aswel.

My xm with the manual prv v6 drives very nicely, gives power when you need it and runs great stationairy, however only when letting go fully of the gas pedal and when giving gas again from closed throttle, it jerks slightly after half a second. You could be redlining the car and letting the pedal go untill the last mm and everything runs smoothly, but if you let it go all the way then it jerks. Working the pedal very softly and smooth does not change this.

Things that already have been changed:
Lamda sensor
Spark plugs
Knock sensors
Clutch


What could cause this and where should I look?

Kind regards!