I’d like to know if you sort it because we have a 04 plate connect tddi with similar symptoms it will boost till about 2.5k revs then goes completely flat I’ve checked the turbo and it spins fine, revved it and can hear it and see it has no splits in hoses and the hoses swell where it’s creating boost, I’ve even had the turbo to actuator pipe off and it still won’t boost any harder or past 2.5k ?