Vibration at high speed

[Happypappy]

Hello all,

We've recently bought an XJ6, diesel on a 07 plate. The car is lovely, fantastic and only covered 7000 miles when we bought it. It seems the previous owner was a little timid as a couple of days ago the red and amber lights came on with reduced power and it seems the filter was choked to death. Jaguar cleaned it, changed the oil and all seemed well.

Determined not to let that happen and to make sure all was well we took it out for a spin on some fast roads. Now obviously you can't go over 70MPH in the UK, but just for sake of argument, in theory of course, lets say we did.

It's as smooth as silk at 70 but as you creep towards 80 you start to feel some vibration in the cabin as well as the wheel. When you get to 90 there is definite vibration and increased noise. So much so that if you were in Germany on a long cruise your hands would go numb eventually. The vibration doesn't increase if you keep pushing it, but stays the same.

I don't think it's wheel balance as the vibration isn't just in the wheel but genuinely feels like the whole chassis is being vibrated.

Any ideas?? It's going back to the dealer to take a look but not for a week so I'm keen to have some ideas or at least some good questions to ask before then.

Any help much appreciated. Thanks...