Hi so i bought a diesel mondeo CHEAP because the guy thought the turbo was shot, its a 2004 (04) tdci 115 (euro 4 i think as egr has electric plug and vacuum hose) it has low power up to 2000 revs then shoots off leaving a cloud of black smoke! even tho i love this "feature" when someone is driving up your arse and you can smoke them out it isnt great for day to day driving, so looking at forums on here i typed in the symptons and everyones says its the EGR, so i thought id give it a clean but nothing (im an amatuer so dont think i did it well!) next i read about blocking the egr and this is where my confusion sits

I have a EGR that has an electrical plug going to it AND A Vacuum hose (people only seem to posting issues with either electric or vacuum) so as i dont have a plate to block it with yet i thought id try blocking the vacuum (with a screw) and the unplugging the electrical plug and hey presto NO SMOKE and low power back! it didnt seem to pull as much when the turbo kicked in but did seem to help alot (only drove a mile or so)

so my question is... what is my PERMANENT solution to this?
can i use a blocking plate?
if i dont make a hole in the plate will this damage the engine? (euro 4)
if i make a hole will it make any difference?
do i leave the cable unplugged or will this cause a sensor issue?
if there is a split in the air hose at the bottom of the egr will i still have to repair if im blocking it?

THANK YOU SOOOO MUCH FOR EVEN READING ALL THAT!!