Update :
Yesterday a i replaced my fuel pressure AND fuel volume regulator.
I drive 70km on a very easy tempo without any issues.
Today , i drive it again and the problem appears
I need to drive sportive to get the problem disappear for a while (works every time)
So this was not a fix for the problem.
But i have the idea the car runs a little bit better.
It looks likes it responds better on throttle and pickup more easily from lower revs. Also it looks like the mileage/usage is better.
So it looks like 200 euros on parts was not all for notting..
Maybe important info :
I noticed this problem first time a few months ago.
This was very short after a new diesel filter...
I cleaned out my diesel filter house already and replaced a fuel line with a bad rubber connection. There are no air bubbles for so far i can see.
But what if the new filter for example is more resistance then the old one?
Thats why i going to replace the filter with a new original one...