Focus 1.6 TDCI - Loss of power at speed. Possible issue spotted.

[Limakilo]

I had an engine malfunction light come on. Checked the car manually for DTC codes and none appear.

Physical signs; loss of power. Noticeable at 40mph+. Will go up to 70mph (unfortunately was on a 300 mile drive). Notice a very faint exhaust smell in cab, apparently nobody else can.

oil was due for change, and filter. Both have been changed, loss of power isn't as bad. Suspected DPF issues through research but no other warning lights about that.

Took the engine cover off to hopefully find a split hose and some oil mist. Discovered this;

In the attached image, seems to be oil pooling in one of the cylinder/injector bases.

I'm hoping it could be a washer that needs replacing?

 

Any help would be great!