Why do i get this warning? It appears "restricted performance" in red colour after 30 - 40 km in normal driving conditions, or when i drive with speed over 140 km/hour.

 

It tells you there is a problem and the engine is being restricted to reduce the chance of causing serious damage. Get the codes pulled and read - that will tell you why it's being restricted

 

Yes. Please post the codes when you get them.
We can help then.
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Thanks for your answers. I resolved the problem with "restricted performance", but just partialy, even thoug i paid 1500 euro. It was a problem with the air intake manifold and the body throtlle, and i replaced them at a local official Jaguar dealer. But, after a week, appeared rattled, rhythmic noise, like bass sound, correlated with acceleration and engine speed, in the air filter box. When I lift the lid of the box from the air filter, the noises are heard even stronger. Please help me with suggestions. Thanks.

 

WE need to know the year and engine in your XF?

 

The engine is AJD-V6 2993 cubic centimeters biturbo turbodiesel and the year of fabrication ia 2010.

 

Probably not related, but...………...Is the air filter box secured in place? The lid doesn't normally lift up very much after you undo the clips and to change the filter for example, you can undo the small (10mm) bolt at the front lower edge of the box to allow easier access when changing the filter. Maybe the box wasn't fitted down properly and what you're hearing is a vibration/resonance when the engine is drawing air. A long shot but I always like to look at the easy, cheap fixes first.

 

Thanks, but i checked the air filter box and it is fixed on position. The local Jaguar dealer told me that the sound comes from the engine, and it is caused by a valve does not work properly and they have to remove the cylinder head in order to check that. So, i need a second opinion, because this is a complicated operation, and i must be sure that the dealer is not wrong.