Turbo Early Discharge

[rockafellqeinstien]

if its dropping boost all of a sudden, I would say it is intake related (as 90% of issues I have found are). Coils plugs etc cause different sensations.

pressure test your intake if you can but it seems like when boost gets high enough it dumps it like a faulty BOV valve or a bad pipe connection but the hole would have to be big enough to dump a lot of air. a tuner could do this on a dyno and look for the leak.

to take the bov out of the equation take it off and block the outlets and see if its the same symptoms.

It could also be the boost solinoid. you could always run a hose direct from the turbo to the actuator and see if it still happens (run turbo with the waste gate full upen at all revs) will build boost slowly but might show if its related

[Wenier]

Sounds like coil issues to me with them breaking down underload. Hence the ability to run the engine out with half throttle. As said get some ford ones, and also reads like a generic tune. Is it?

Must have the Volvo duoprop I think Ralph.

[ratter]

sounds like a torque management issue but way too many things it can be to make a decision based on the description