Passat V6 TDI: Troubleshooting & Common Problems

Hello everyone, great forum.

I have the following problem:

I drive a '99 Passat 3B V6 TDI, and I've already replaced the mass airflow sensor (MAF sensor) four times. Each time, I had to pay a deductible of 150 euros under the goodwill policy. This problem is well-known to VW, and according to the workshop, the cause is a design flaw in the air filter housing. This allows moisture to reach the MAF sensor, causing it to fail after about 2 months. If you think they would replace the housing at VW, you're mistaken. I have to pay for that myself (150 euros). Has anyone had similar experiences or a solution?

Okay, here's my current problem:

Last November, I had a new timing belt installed (750 euros), and at the same time, I received a new mass airflow sensor (MAF sensor) at a discounted price of 150 euros, thanks to a gesture of goodwill from the factory after I filed a complaint in Wolfsburg.
Since then, my car has been consuming an average of over 10 liters per 100 kilometers. Now I've noticed that it's also producing a lot of smoke (light gray) and doesn't have the same acceleration it used to (and the top speed is also lower).

What could this possibly be?

Another VW workshop suggested that there might be an error related to the timing belt installation (timing, fuel injection pump, or turbocharger) and that I should go back to my original workshop because they need to fix it.

Is there a way to put a stop to the incompetence of these workshops?
I'm really fed up with this and have now ordered a diagnostic system.
This afternoon, I have a service appointment. I'm already curious to see what's broken this time and how much it will cost to fix.

I hope you have some advice!

Best regards,
Oliver

Hello.

Regarding your first point, there is information available in the error database.
/viewtopic.php?t=1266&highlight=v6+mass+air+flow+sensor

I would have point number 2 fixed at the workshop. The car was running well before the timing belt change, right?

Best regards, Rainer.

I will report back later on what the workshop said.

Okay, after Volkswagen worked on my car for about 90 minutes, they came to the following conclusion:

Smoking is normal.
Lmm is fine.
The air filter was clogged and has been replaced.

I'll believe that when I see it!!!!!!!

Hopefully, I'll have a diagnostic cable soon.