Loss of acceleration

Unfortunately, we don't have a manual on this vehicle as it is not offered here in the USA, but a diesel engine is pretty basic and the same no matter where it is.

So here are a couple guides that will help with this issue. Clearly this is on a gas engine, but most all the issues are the same.

https://www.2carpros.com/articles/engine-has-low-power-output

https://youtu.be/U1RoG3I-Oww

More than likely you have an issue with the amount of air coming into the engine, the turbo, or a fuel issue.

Assuming this is a turbo engine which it appears it is.

I would suggest checking the charged air system for air leaks. This would be from the air filter to the turbo and make sure there are no leaks or restrictions. Then the charged side is from the turbo to the intake manifold.

I suspect you have a leak in this side of the intake that is not suppling the proper amount of air.

The way to check this is you need to put compressed air to the tubing from the turbo to the intake and use soapy water and spray down all the connection points looking for bubbles.

Please run through this and let me know what you find. Thanks