Engine knocking/clunking sound

So, I own a 2003 Seat Leon PD150 and it started making a knocking/clunking sound. The engine temperature doesn't change the sound. The knocking sound is directly linked to RPM. Knocking on higher RPM sounds like metal parts bashing together. Knocking sound is not even noticeable when pressing the anti-shudder valve manually to the closed position.
I read codes with VCDS and it shows 17552 MAF error and 17964 Charge Pressure. The cam cover was taken off and everything looked pretty much ok.
I am losing hope in this. The ecu has been remapped and the turbo boosts 1.5bar. Also when the problem began I noticed that the turbo was acting weird, it did boost 1.5bar as normal, but when I released the throttle the boost gauge showed that it went from 1.5bar to 1 bar then bounced back to about 1.1 and then down. Almost as if the air was jumping back and forth somewhere? I also removed the EGR downpipe and plugged it.
Please tell me what could be the problem?
Thanks.

Here is a few videos of the sound.
https://youtu.be/ic94YjtZd_8
https://youtu.be/VxZ6d2Xysw4
https://youtu.be/3Onho_mD9Ew

Have you checked the cam? I think that's where I would start.

Metal Man said:

Have you checked the cam? I think that's where I would start.

Click to expand...

Yeah, the cam seemed to be fine.

I can't think of any problem where closing the anti-shudder silences the sound. I am completely out of ideas why closing it would do that.

A leaking injector could cause a knock sound (is "nailing" the name of this?) . The leaked fuel ignites while the piston is still traveling up. Also the piston temperature rises so much in severe cases it can melt the piston. It usually destroys the glow plug in the cylinder.

Okay so I bought a spare car for the winter and I am gonna check the valves at spring when the snow melts. I think it might be a blown lifter or valve.

So, I took the cam off and the cam was busted. Also 1 lifter had a hole in it and lifters were all around bad. I ordered INA camshaft and INA lifters.

Picture of lifters. https://imgur.com/KwKEKwt