Boost Issues : Please Help

[palmerv50]

Any idea where I go from here?

Boosts fine then cuts boost for no reason. Turn it off, turn it back and boosts fine, then looses it for no reason
New turbo
New actuator
DPF sorted (gutted and mapped)
EGR sorted (blanked and mapped)
New MAP Sensor
CEM Cleaned
Boost pipes checked, no cracks etc and smoke checked

Only fault is an Air Con fault that shows up

Me and three mechanics so far are stumped

[Simmy]

boost control solinoid and vac lines

[IainG]

Hi
If you have the 2 or 3 control solenoids swap them over and try, I had an intermittent loss of power and found one of the rubber elbows on one of the vac lines with a split. Easy way just "T" in a vacuum gauge to the vac pipes, should be about 20" vacuum then move all the pipes about and see if the vacuum drops at any time. Also the vacuum connections can become loose giving similar issues. Diagram attached for my car if any use(from another member on the forum)