Transit power loss at motorway speeds

[caffeinedealer]

Hi everyone,

I would need you expert opinion on an issue I'm stuck with. At work we have a 2018/19 Transit with the 2.0 TDCI engine that keeps losing power at motorway speeds, at around 120 kph it randomly starts decelerating like you jumped off the throttle. It stays this way 10-15 seconds and then like nothing happened everything carries on. During this "event" it doesn't make a difference if you change gears, or try to do play with the throttle.

Forscan gives no relevant error messages. Tried to log live data, such as boost pressure, delivered fuel, injector quantity deviation, etc. but nothing seemed out of the ordinary. All injectors are providing the same values give or take, no major difference.

Fuel filter has been changed, someone who previously serviced the van in it's previous life used some grease or silicone on the threads of the fuel filter housing. Sadly this didn't make the problem go away, even though it runs smoother and feels more powerful.

The only progress I was able to make is that now I can consistently replicate the fault by driving on the motorway in 5th gear, accelerate up to about 3100 rpm and then it loses power every time. At lower speeds it doesn't have any issues revving above 3100 rpm regardless what gear it's in.

Did you have anything similar? What values would you look at in Forscan's live data that could point me in the right direction? Thanks in advance.