In view of your current vehicle test I now firmly believe you have a sticking EGR valve as hesitation and low power under 2000 rpm happens when this valve isnt operating correctly.
You could try removing and throughly cleaning or replace EGR and all should be well.
It might also be worth cleaning the intake manifold pressure sensor as this also can be a problem with your symptoms.
You have begun the process of elimination to a tricky problem,hang in there you will get there.
Thanks for your reply. I already took the egr valve off a while ago and it was only lightly sooty, i cleaned and oiled it anyway, the spring is very strong so its unlikely to ever get stuck open, maybe i need to take it off and test it again, now that i have a vacuum gauge i can test its movement while its out.
The MAP sensor was replaced with a new oem one.
TESTS DONE TODAY
EGR valve tests using vacuum gauge - please note opening egr with my vacuum gauge causes the engine to stall is this normal?
ISTA air mass system test still reports the egr as faulty.
ISTA pneumatic egr tests, both tests cut the engine out
0 - 10 - checking egr holds pressure (it does)
10 - 30 - egr operated with vacuum gauge & engine cuts out
30 - 50 - vacuum reading before pressure converter and it goes off the scale
50 - 2.07 - vacuum reading after the pressure converter
Acceleration with foot to floor, all components are connected, there is hesitation and low power below 2500rpm, my foot is flat to the floor, a knocking noise appears around 2000 to 2500rpm, this noise is only heard at this point in the rev range and only brought on with the foot flat to the floor ie not with gentle acceleration.