Audi A4 2.5 TDI Turbo Lag: Why It Happens?

Normally, I would experience the "boost" or increase in power at approximately 2000 RPM. Below 2000 RPM, there was absolutely nothing – then suddenly, it would kick in properly.
Two months ago, the mass airflow sensor (MAF) was replaced, but it barely provided more power and produced a lot of black smoke.
After replacing the mass airflow sensor, everything worked perfectly for about 3 weeks!
Now the power doesn't kick in until around 2700 RPM, and it's not as sudden as before.
I did a log using VAG-COM today.
It would be great if you could take a look at this. Maybe you'll notice something. There are no errors in the "engine electronics" fault memory. Unfortunately, I don't have enough technical expertise to properly interpret the log data...


Log:
[Edit Admin: Wenn Du hier Hilfe erwartest, solltest Du Dein Log auch hier zur Verfügung stellen.]


Here's the link to the Screenshot, and below it is the log from VAG-COM.
/viewtopic.php?p=156319#156319

Does your phpBB forum have the ability to upload files?

Okay, I'm ready. Please provide the German text you want me to translate into English.

In the log diagram, you can see that when the engine is running at full throttle, the mass airflow (MAF) value fluctuates quite a bit, and so does the turbo pressure. Is this normal, or should the MAF value be consistently above 750mg/s when running at full throttle?

I've only uploaded two screenshots of log data from two different runs: one with an LMM that is 4 weeks old, and one with a brand new one.
LMM is...
Turbo pressure is...
Accelerator pedal.
Engine speed is...

Is this fluctuation in boost pressure and mass airflow rate normal?

/viewtopic.php?p=156319#156319

Quote:

Should the value from the mass airflow sensor (MAF) be constantly above 750 mg/stroke at full throttle?

Actually, yes!

Best regards, Rainer.