2002 vectra 2.2 dti p0400-f8 egr feedback signal code

[robbocop33]

So, very rarely engine check light will come on accompanied by slight loss of power, probably some kind of limp home condition.
Anyway egr valve is completely cleaned and free moving. I used my bidirectional scan tool and commanded the egr to close and open, this worked well so wiring good, but, randomly sometimes i would command the egr open to 100%,then when i tried to command it closed it would stick at 100%??
This would be cured by a slight blip of the throttle! Then it would close, anyone any ideas? I'm thinking faulty solenoid maybe?
Car idles fine and drives (albeit underpowered) , even when engine check light comes on, no stalling etc.