Ok the most common fault we see regarding your issue is a partially blocked fuel filter
This is more noticeable when demanding power
These fuel filters on the 1.6 TDCI s are prone for partially blockages suspectably caused by wax debris from the internals of the filter (as this filter comes. As a complete unit and cannot be stripped )

Other faults on these 1.6 TDCI s regarding your fault are fuel pressure sensor wiring issues (usally the wiring is too tight on the loom and causes an intermitent loose connection causing a hesitation feeling when driving
Also the EGR valves were prone to water ingress but this was more so on the 05/06 models thus EGR fault would also give you black smoke

I would suspect a fuel problem from your description

The best way to clarify exactly what sub system the fault lies in is to have a diagnostic fault code check carried out as this gives more clarity on this type of issue

The best way to diagnose a partially blocked fuel filter (without just replacing it ) is to have the vehicle driven with a data logger connected to it this allows the technician to monitor the live data from the vehicles sensors etc
If on data logger the fuel rail pressure drops suddenly them you know this is where the issue lies

Partially blocked Fuel filters are the most common fault though

These filters shod be replaced every 37.5k or 3 years which ever comes first
But have seen them changed as early as 20k for this type of fault

makz85 je napisal/-a:Se še kako drugace rece ker gledam v tecdocu in ne najdem nepovratnega ventila...? Ta ventil se nahaja na pumpi?

lisko je napisal/-a:V samem filtru goriva (ohisjo) je verjetno nepovratni ventil. Si sigurn dobro sestavo? Ne vlece kje lufta? Ce je vse ok potem za filtrom prerezi cev in daj u mes nepovratni ventil(med filter in pumpo).