Golf 3 TDI 81kW power issues

Hey everyone,
I'm not very familiar with technical terms, but maybe someone will understand me!
Here's my problem:
My Golf is having problems with acceleration. The thing is, it only happens occasionally. I've noticed that it usually happens when I'm accelerating from a low RPM in a higher gear (like 4th).
In the spring of 01, the engine would repeatedly switch to a limp mode when it needed to provide power (e.g., when driving uphill) after a cold start. After turning the engine off and on again, everything would be fine. The workshop read the error memory, but it often showed nothing, and the first time there was an error message like 'boost pressure...' (I don't remember exactly, but it might have been from the previous owner). Then they wanted to replace the motor control unit, but that was too expensive for a rare problem.
Then someone told me to try replacing the mass airflow sensor. I did that too.

Here's a tip for everyone: A mass airflow sensor (MAF sensor) from a Golf 4 is significantly cheaper than one from a Golf 3. You just need to change the connector because it's round instead of square.

Since then, it's been running better, but not perfectly. I find the engine feels slower in very warm weather compared to cooler weather. Also, when the car is fully loaded or I have to tow a trailer, there's a kind of stepped acceleration. However, it's only gone into limp mode twice in the past year. As I said, I mostly notice it when I shift up early (low RPM) and then fully accelerate (e.g., accelerating out of a village in 4th gear).
Should the mass airflow sensor (MAF) already be defective after about 10,000 km?

Please help me!!!!!!!!!!!

Hello,

I can only advise you to have the error memory read. However, make sure that everything is actually printed out. Many workshops often say, "Nothing to worry about, everything is fine."
You should also have a measurement test performed. As always, caution is advised to ensure that all requirements are met (see also the error database).
If you post the error log and the measurement values here, someone will definitely be able to help you.

Hi,
What exactly is a measurement run, what is done during it, what equipment is needed, and who has access to the equipment? Say: Where can I get this done?

Hello,

"Important engine parameters can be read out via a diagnostic system. During a test drive, these parameters are measured once at idle and once at full load (refer to the error database under 'Target values of the data blocks' for the exact conditions). This includes parameters such as boost pressure, injection times, injection start, various switch positions, and more."
For such a diagnostic test, a diagnostic system is required. Most authorized workshops have one. Privately, you can also purchase an adapter including software, or you can build the adapter yourself (see various posts here in the forum, and also the link under "Tips & Tricks"). Furthermore, a PC (ideally a laptop) is required for a private adapter.