I've got an "Insufficient Flow" error on the EGR system, the light has been reset a few times but always returns within 10/20 miles at low speed usually.

I checked all the pipework out which seems to be ok, but I noticed a few of the pipes were oily inside near to the vacuum solenoid block on the bulkhead, is this normal?

I'm still not sure on whats at fault, I suspect the EGR valve as if I attach a pipe and try to suck through it I am unable to hear the plunger in the EGR moving.

My question is, is oil in this area normal or is there a chance a diaphragm has ruptured and is passing oil.