Hello everyone, I’m a newbie to the forum and hope someone can help me.

I shall start at the beginning..
I have just fitted a second hand disco 5 engine into my l494. Both 3.0 tdv6 gen2. My sport is a rare one with no add blu.
All went well, except for a noise coming from the drivers side Egr flap. It only starts when vehicle is up to operating temp. The vac system seems to just bounce the flap open and shut constantly. The noise sounds just like the vac pump itself sucking away. I don’t understand why it’s temp related? I swapped the egr and the control solenoid located by the vac pump. I can’t find any idiot guides on where each vac pipe goes. I don’t think I have fitted them incorrectly. I haven’t swapped the vac pump itself yet. It looks like a tight job. But again why does it only happen when it’s warm?
I really hope someone can shed some light on this for me. Cheers