Car loosing power when warmed up

[Conor_DTS]

My 306 d turbo usually sits at 70 degrees when driving and the car goes fine and has plenty of power, its got a Bosch pump screwed 1 full turn and garret turbo screwed 2 and a half turns, when driving around town etc the temperature goes up as u would expect but then the idle drops slightly and the car looses a lot of power like it will hardly spin the wheels and just feels really dead and sluggish. Has anyone else experienced this before?
Im thinking mayb heat soak or something like that but im not sure as i had 2 other d turbo's before this one and none of them did it and it didn't happen with this car when it was standard.

Any help would be great as it has my head fried lol

[Kwik]

check the oil breather that has a bit that clips into the intercooler. if it drops and collapses on it self will cause the symptoms you saying

[Conor_DTS]

yea it is hanging down, il get that sorted. Thanks