Acceleration fluctuations

Hello.

While driving my Passat, I've noticed fluctuations in acceleration.
These are particularly noticeable in the 4th and 5th gears.
When accelerating, it starts pulling around 1600 rpm and experiences a fluctuation at approximately 2200 rpm (as if something were pushing from behind). Then it runs smoothly for another 3-400 rpm before the power gradually decreases.
What could that possibly be?
I've already read articles about LMM (likely referring to a specific type of motor or device), but I'm not sure if I can apply the 'diode trick' to my own situation.
I still don't have a laptop to perform measurements.
Thank you.

I had the same problem. I replaced the new catalytic converter and it started working again (it was a bit sluggish at first, but after a few kilometers, letting it sit for a while, and then driving again, the car regained its power).

Best regards, WarLord.

Thank you very much.
It was the LMM (likely referring to a mass airflow meter), and the acceleration issue is now resolved.
We want clear statements like that, not endless discussions where reading makes your eyes burn.
Thank you again.