Poor AFN performance

Hallo zusammen !

First of all, congratulations on the forum! It's absolutely fantastic what you've put together!!
There's nothing about real-world experience here, and you can get the best insights from you guys!

But even so, I've been reading for months now, straining my eyes! Please give me some tips that will help me progress.

"I've been driving a Passat 35 (model year 05.96) with an AFN engine for 3 years now, and I have the impression that the performance has gradually decreased. A recent power test showed approximately 20-25 horsepower less! I work at a company that sells this brand, so you can imagine my approach to troubleshooting... but I haven't had any success!"

Okay, here are the facts: - No errors in memory.
- Measurement data blocks are OK.
- Check turbocharger boost hoses for leaks.
- Nozzles Refurbished
- New: Mass airflow sensor (MAF), boost valve, EGR system deactivated, engine control unit (ECU), turbocharger, overhauled engine.
all vacuum lines.

As you can see, I've checked and inspected everything. EVERYTHING except the VP-37 fuel injection pump! It has been partially disassembled already (I read something about it on the forum), but no defects were found. My question is, does anyone have experience with this type of fuel pump?

Best regards, Maggo.

"Good day, I wanted to ask if you've already found the solution to the problem because my car (AFN engine) is experiencing the same issue."