Boost "Hesitation"

Hello.
A4 Avant, 140 kW, 1.8L turbo, Engine code: BEX, Year of manufacture: 2003.

My Audi A4 Avant jerks or hesitates when accelerating above 3000 RPM.
Subsequently, I plotted the boost pressure in a diagram (see attachment).

red: boost pressure (target value)
green: boost pressure (actual value)
yellow: Charge pressure control valve (N75) control.
purple: adaptation, boost pressure control.

Both measurements were recorded during acceleration runs with the engine running at full throttle in fourth gear.
The left half/curve of the diagram represents the jerky acceleration, where each spike in the boost pressure (actual value) represents a "jerk." The right half/curve represents normal acceleration without any problems. As I suspect, the "jerks" are caused by the spikes in the boost pressure (actual value). What are the causes of the "jerking" or the peaks in the boost pressure? Is this related to boost pressure regulation, or are these boost pressure spikes caused by something else?

Thank you for your tips.

Quote:

Subsequently, I represented the charging pressure in a diagram (see attachment).

The corresponding log file would be helpful here, as it's missing information such as the timeline.

What happens if something is accelerated more gradually, since - many high-voltage problems often only occur at full load. Whether an error is always reported to the control unit (STG) is not always certain.

Unfortunately, I don't have a log file because I only took a Screenshot. Should I also log the data during the jerky acceleration, would that be helpful to you, or would that data need to be specifically related to that particular instance?

When accelerating gently, there is no jerking; it only starts to occur when the accelerator pedal is pressed about three-quarters of the way down. Initially, the jerking didn't happen with every full-throttle acceleration, but now it happens almost every time. Exception: the right curve/diagram half.

If you record the log file and use KDataScope, you might be able to identify something.

Please find the log file attached, which includes both "jerky" and normal acceleration events. I've noticed that the "Adaptation-Boost Pressure Control" value changes during normal acceleration, but remains constant during "jerky" acceleration. What exactly does the "Adaptation-Boost Pressure Control" value represent? Thank you for your ideas and suggestions.

Okay, so I've now replaced the N75 valve, and there was also a vacuum hose running from the N75 to the turbo that had been chafed by a clamp on another hose. Additionally, I had to remove a hose from the crankcase ventilation system, which was full of brown sludge, and this sludge extended all the way to the valve in the camshaft ventilation system, likely indicating a faulty head gasket. That's at least what the "stuttering is gone" message says, but I can't say for sure whether it was due to the N75 valve or the vacuum hose.

Thank you for your effort and assistance.

Thank you for the feedback!