Peugeot 205 turbo diesel runaway idle

[MadeinWigan]

My 205 drives well but can suffer from a strange idle most of the time. If left say idling it will go in a cycle of stuttering and then building up to a heavy rev which then calms down. I think this video shows it well

http://youtu.be/x-_x_CHq5wg

What would you suggest is the cause?

Thanks

[powerstroke]

Possibly the turbo or engine breather is passing a little oil so it builds up until there is enough to be sucked into the inlet manifold once it starts to run on a bit of it the revs rise and it gulps the lot in revs up and then calms down !!
or there is a govennor issue in the pump i.e. something sticks , try running it with the hose to the manifold off see if it still does it and there is much oil in there or being blown out when its running, if it still does it its pump trouble....

[MadeinWigan]

Thanks. It's strange, if I leave it idling facing uphill there is no problem but if it is facing downhill it starts misbehaving.

[E-bmw]

If you bear that in mind & look at the plumbing around the turbo very closely, you may find that information helps to decide where the oil is getting into the turbo from.