VAG-COM Values: LM (Longitudinal Acceleration)

I've finally become the owner of a diagnostic adapter, and I've used the shareware version of VAG-Com 404 to thoroughly measure and log the performance of my AHF (air handling unit). After creating some impressive diagrams, I only noticed one inconsistency:
Basically, I wanted to check if my mass airflow sensor (MAF) is starting to fail again, so I first logged block 003 and then compared it to the expected values table.

At idle, I'm getting approximately 430 mg/H (should be 295 mg/H).
I'm attributing this value to the "broken" EGR valve .

When accelerating from approximately 1600 RPM, the SETPOINT value jumps to approximately 850 mg/H, and the ACTUAL value increases to approximately 830 mg/H. At 2100 RPM, the ACTUAL value suddenly jumps to 995 mg/H, even though the SETPOINT value remains at 850 mg/H. Afterwards, the ACTUAL value immediately decreases again, and at 2350 RPM, it settles back to approximately 830 mg/H.
The IST value then steadily decreases to approximately 4150 RPM, where it reaches 770 mg/H. Does this now indicate a weakening mass airflow sensor, or does it not ?

In addition, I also logged data from block 010, and there, too, I measured an actual air mass of approximately 800 mg/H during acceleration (with some values as low as 770 mg/H). This means it's actually still below the target value. The intake manifold pressure, ranging from 1700 to 1900 mbar, is also at the lower end of the range (except when changing the accelerator pedal position from 0 to 100%, where a peak of 2000 mbar occurs).

Given these values, is there a need for action, or have I misinterpreted something? Since I'm still relatively new to this area, I could probably use some expert advice and insights.

Sure, here is the translation of the text from German to English:

"MFG" is an abbreviation for "mit freundlichen Grüßen," which means "best regards" or "sincerely." It is commonly used in German-language emails and letters.

Hello,

If your charge air cooler system, including the EGR valve, is definitely airtight, then the mass airflow sensor is definitely faulty.
Regarding the "jump," you should also take a close look at the plugs and cables, just to make sure you don't have any contact problems or worn-out plug pins.
The need for action depends on your budget and your personal tolerance for inconvenience: the car is simply getting weaker. Depending on your driving style, fuel consumption may also increase slightly (e.g., because you may now rev the engine more to accelerate quickly).

However, nothing can break or malfunction as a result.

Best regards, Rainer.

Rainer K. wrote:

If your charge air cooler system, including the EGR valve, is definitely airtight, then the mass airflow sensor is definitely faulty. Regarding the "jump," you should also examine the plugs and cables, just to make sure you don't have any contact problems or worn-out plug pins.

Generally, I agree, but I think the boost pressure shouldn't be completely ignored.
If the system were to experience occasional "spikes" (for whatever reason / next test subject), the mass airflow sensor (MAF) value would naturally increase, especially within the middle RPM range, even if the MAF sensor itself is perfectly fine.

Hi!
Thank you for the answers. The LMM seemed very suspicious again. However, I will still consider whether to replace it immediately. But if I'm already paying taxes for the performance, then of course I want to take advantage of it .
At least, this thing isn't as expensive as my ESP was a year ago .

Since describing my measurements can be a bit complicated, I've included some graphs here to illustrate them.
(As stated: Audi A3 AHF, year 1999 - Mass airflow sensor (MAF) replaced at 95,000 km - currently at 158,000 km).

I hope these links work...