Hi Mate,

I had a similar issue with a 2008 30d. I however had quite a few codes, MAF sensor fault, Oxygen sensor fault, glowplug faults, DPF issues, and finally EGR control deviation fault.

Ended up replacing the MAF which made no difference, then started looking into the EGR, removed it to visually inspect, was relatively clean (with 320,000kms) and opened freely.

Reinstalled looked to see if it would open through the booth you highlighted above and there was no movement.

Eventually went through all vacuum hoses and traced it back to the pressure converter (also noticed when idling it was making a sort of quacking noise which has since gone since replacing).

Installed a new one and was all good from then on.

My suggestion would be to check all vacuum hoses to ensure no cracks or breaks.