V6 engine with intermittent power loss

Hi,

What values should I have plotted on a graph or measured during a diagnostic run using VAGCOM?

It's a 2000 A6 Avant with an automatic transmission and Tiptronic, equipped with an AKE engine (2.5L).

Sometimes it runs well, sometimes not (sometimes it only manages 170 km/h), and there are no error messages stored.
The control unit was replaced recently due to issues related to Russian components.

Today, I checked the air mass value (last reading) in block 00, which should normally be between 50-70, but it was at 86 (at idle). Then I took a ride, and after that, it was at 63, so it was back within the normal range.

The LMM (likely referring to a mass airflow sensor) was actually replaced about a quarter of a year ago.

The problem occurs especially when it's warm, if the car has been standing in the sun all day, you immediately notice it... Also, the acceleration is strange, and sometimes it seems like something is sticking, so the transmission doesn't quite know which gear to shift into. Then it might get stuck in, for example, 3rd gear for 10 seconds, and then finally shift into 4th. Ideas??

And maybe someone can tell me if 52 degrees Celsius is a normal value for the fuel temperature in this type of car? Because a workshop said that the part might be compatible with another model.

Chrisi.