Just to let you know that I have fixed the fault on this vehicle.The only way I could trace the blue and black vac pipe was to remove the inlet mainfold. Just above the starter moter, there is a pressure regulator mounted to a plate. The regulator was covered in oil and the electrical plug conector. Replaced with new regulator, replaced mainfold gaskets and then replaced EGR valve which was coked up.No more noise and now idleing correctly