V50 1.6 vibrating on acceleration

[Mikaell]

I have this V50 1.6 diesel from 2009.

The car is vibrating slightly on third, forth and fifth gear on acceleration or under load going up-hill. Otherwise runs nicely. I thought this might be from a full fuel filter and on replacing it I compared by blowing air through the new and old filter there was major congestion in the old filter.

After replacing the fuel filter I got the same issue as several with air trapped in the lines and no fuel being pumped up by the fuel pump. I read this model don't have a tank pump and therefore needs proper priming.
I therefore installed the hand-pump illustrated in the picture below to enable proper priming.



The car now is more difficult to start. I can see through the transparent fuel lines several cm of air pockets are accumulated in the airline and this causes the starting issues as resolved by some (10) squeezes of the hand-pump.

The vibrations on acceleration remains and air is getting in somehow.
Anyone recognizes these issues and like to share possible solutions? Have thought on adding an extra one-way valve to the fuel line to prevent fuel to pore back into the tank, but like to see a drawing of the V50 1.6 2009 fuel system, if anyone have a illustration to share, before starting to modify it.

I have tested full turns and notes no issues with the drive axle joints.