u/Global-Box-1406

I have a 2019 BS4 Interceptor and it has done 20000 km, It pulls fine until 5th gear and 160kmph but after that it just holds steady at that speed at 5-6k rpm.

I got the throttle body,fuel injector, Spark plugs cleaned ,tappets adjusted, ,and it's still the same.

The air filter(ngage hyper flow) is a bit dirty has done 5000 km.

6000 km since last oil change.

What could be problem?