Engine boost problems

[pugacs7]

1.9 tdi AFN here, pulling all gears good, except when more than 2300-2500 rpms, kinda like click and engine loses power and accelerate very slow, ignition off and on, power is back again. Also, when at 90km/h power goes away, can get to 110/120 kmh only after some time.
Decided to disconnect turbo vaccum hose, a little bit worse acceleration, but can get to 140/150 kmh easily and doesn't click and power dont go away as used, but always slower boost or smth like that.
What can be the cause?

 

[P2B]

Limp mode due to turbo under/overboost.

Diagnosing and Fixing Limp mode for A4 1.9TDI [low power troubleshooting]

Diagnosing and Fixing Limp mode for A4 1.9TDI By Canadian Grizzly Read the entire post prior to jumping to conclusions. This is a general overview on how to diagnose and fix a A4 1.9TDI that goes into “limp” mode due to an overboost of the turbo. While I’m by no means an expert I’ve gleaned...

forums.tdiclub.com

 

[Gothmolly]

Yeah, limp mode. Lay off mashing the pedal down, roll the power on and you can probably avoid it. Do you have any power mods? These things LOVE to boost if you add fuel. I can't go above about 2/3 throttle without hitting 20psi and throwing an engine light.

 

[P2B]

I can't go above about 2/3 throttle without hitting 20psi and throwing an engine light.

You and the OP both have faulty boost control systems.