Hi Paul,

I was completely unaware that vac reading will drop when turbo pressurizes. I understand the initial drop on throttle opening but thought turbos would react in the same manner as a normal aspirated engine. ie vac reading would recover to 19-21"hg. Something new learnt today. Yes, 15" is low but garage assures me that cam timing has been checked. Customer has vehicle back whilst we figure out where to go next.

Regards

Pete M