Astra H, Z17DTR strange idle problem

[astraF]

Hi all,

Car: MY08, Astra H, Z17DTR
During the last few month I met in my workshop many times with the following problem.
The rpm is fluctuating at idle speed ( and if I even use cruise control and set the speed e.g on 80 km / h on flat road, I can see the rpm is fluctuating a little bit +/- 50). But worsest thing is that the engine sometimes suddenly stops. Doesn't matter that the engine is hot or cold.
So far many workshop tried to to do something without any succes.
They have changed rail pressure sensor. Mass airflow sensor and EGR have been cleaned, The high pressure pump and injectors are working perfectly. They have been checked on bench. I checked the report and they are great !
I searched on the internet and found that it is quite common problem with these engines, but nobody wrote solutions...

Does anybody know generally what does cause this symptom ?

[astraF]

Ps: No trouble codes stored, and the engine performance is pretty good !

[kratmel]

Perhaps the problem - air ingress into the fuel lines.
 Try to put the transparent tube on the inlet line to the pump and see it in the presence of air.

[astraF]

Thanks for your idea. I will try it 

[asm]

I have this same problem.. but mentioned solution does not helping