Hello

I just purchased a new 2014 Audi Q7 TDI diesel Technique model, with air suspension. The car has a 3.0 TDI engine, and 20inch Pirelli Zero Asymetrico tires.

Ever since I got the car it would have 2 issues when driven on the highway:

1) Steering wheel would shake, when speed would exceed 100km per hour.

2) There would be an engine vibration that in felt mostly in the driver seat,drivers pedals, when speed exceeds 100km per hour.

I went to my dealership, and they did the following:

1) Changed all four mags to a new set
2) swaped my tires for another set of the same tires.
3) Adjusted the engine mounts
4) Did a hunter road force tire balancing and alignment.

After doing this, the vibration in the steering wheel is gone.

However, when I drive the car on the highway, I still get a low rumble vibration in the drivers seat, pedals. The dealer tells me that this is normal for a diesel engine, all diesel engine shake,

However, I have driven another model and i found very little vibration?

Can anyone, give me any ideas what can be done? Or is this normal for a diesel car to vibrate/shake at highway speeds?

Richard