Car came from another garage having had a turbo and an air mass replaced for the complaint with no improvement.

Quick visual check revealed broken intake flap arm
so manifold was replaced.
Given the nature of the fault we tested the EGR Valve which proved to be stuck open and open circuit so this was also replaced.

The fault unfortunately is still evident? As soon as boost kicks in above 2000rpm away she goes!!

Exhaust back pressure test proved acceptable (peak pressure of 2 psi at 3000rpm, below that 0psi)

Expected fuel pressure and actual coincides but wouldn't have thought this is likely to cause this particular fault? Is it worth throwing a filter at it??

Any input welcome.