LMM failure on Ibiza TDI AFN (81kW)?

I'm having the following problem:

My car has significantly more power when it's cold, and it doesn't really start performing well until around 3000 RPM. I have a power box from KW-Systems installed, and the potentiometer is turned all the way up. I called them about it, and they told me that my mass airflow sensor (MAF) might be defective.

How can I check that?

Thank you for your help!

Regards,
Monchi.

Hello,

First, I would read the error codes. If there is no information provided, you should perform a measurement run (values are in the error database).
The topic of LMM has already been discussed quite frequently here. Just search for it...