Audi A3 2.0tdi BKD lumpy and stalling HELP!

[Challio]

Hey guys, been looking around for my problem, but there are so many different things which can cause this.

OK here goes, on a cold start it will crank for around 7-10 secs. then most of the time stalls and have to re-start with plenty revs. If i hold revs at a steady 1200rpm the revs fluctuate up and down. As soon as i idle it stalls with a big judder. When travelling on the motorway at 60-70 there is a hesitation on power and sometimes hits limp mode. When pulling up to traffic lights it stalls completely....

Somethings i've done.

New clutch (old one was mashed)
cleaned EGR valve (piston moved freely)
New speed sensor (one near the oil filter)
fairly new injector loom
new MAF sensor
New fuel/air/oil filter etc
Checked tank pump is working (OK)
checked vacuum pipes (seems OK)
checked ohms on glow plugs (fine)
blanked off EGR intake

Here is where I get stummped, when I remover the intake below the anti-shudder valve and leave it loose away from the intake, all stuttering goes away albeit like 10" exhaust but runs fine and can hear EGR valve opening/closing changing tone of engine. As soon as i put it back in then the juddering/stalling begins again.

Can anyone throw some light my way. Is it turbo related with the limp mode.

thanks

Paul