If the unoccupied seat is wobbling enough to drive you nuts then the seat track needs to be tightened up. Some of this could be done with grease....

 

Lithium grease with her or I need the option number on the vibrating seat. Vibrating seat, I hear drives the Harley girls crazy!!!

 

I just got mine back from service with the "unfixed" complaint of a rmble or vibration noise from the back (engine compartment). I did not think it was the seat. I thought that it was either the spoiler fan or something shaking in back. Driving with the service guy in the right seat it did not do it.

Now I am thinking if it could be the right seat. It does it when I am alone.

 

My passenger seat does vibrate sometimes, what I do is I change the position on the seatback just slightly, either up or down, and it stops. Until some passenger decides to change the position again.
Try that and see if it helps.

NOTE: I reach over to adjust the seat with the car moving,
this way I can actually see when the vibration stops.
However, I DO NOT recommend this procedure!

 

I just drive it. Seat vibrates a little at 210km/h but I have other things on my mind at the time.

 

I also have an annoying rattle that's coming from somewhere overe there. To be honest, I'd thought that it's either in the B-pillar (seat belt outlet) or in the panel just behind that by the rear, right passenger seat. It hadn't occured to me that it might be the passenger seat. I've only ever driven alone, so I haven't had the chance to see if adding a passenger alters it. I had a bad rattle in the passenger side door pocket that the dealer fixed a few months ago also. Car only has about 2300 miles.

 

Interesting that this happens on my 987S too, with the sport seats.

Keep in mind, it is a sports car gang...stiff suspensions and thin sidewalls have to have some downsides too...

 

I had the same problem. It turned out to be the left rear speaker bracket.

 

Is option VSS (Vibrating Sport Seats) available yet?

 

The type of vibration I feel is the same you get if you tap with your fist the rear bumper or rear lid. You get a rattle. We first thought that it was the license plate, bt removing it for the test had no effect. The other thing we noticed (dealer says it is normal), is the play in the engine compartment fan. If you tap it with your fist you also hear the vibration.