I own a 2007 Left-hand Drive XKR convert. Approx 76K miles.
For about 3-4 months, there has been a "rattle" coming from behind the back seat.
I have had it in twice for the Jag Techs to take apart the car. I took the tech for a drive and he heard it as well and said it was "definitely not normal".
The sound is similar to what it sounds like when you wiggle and scrape your fingernails back and forth across a paper notepad with full pressure, then add a bit of a metal component sound. It sounds very clear making one suspect it is not too far from the rear passenger compartment. Each sounds "episode" lasts around 3-5 seconds most commonly but depends on driving conditions and frequency of vibrations coming from engine.
Tech has fully checked trunk, spare tire, battery compartment, convert top mechanisms, trunk hinges, removed back seat, and checked suspension. I believe he also said he checked the emergency brake cable.
Sound comes from center of car and is most reliably reproduced when gently accelerating (15-30 mph) over mildly bumping pavement. Can also be heard (but less common) when coasting or lightly braking over similar pavement.
I have never heard above 50mph. It is loud enough to interrupt conversation if radio is off and make passengers ask "what's that sound?"
I have already spent more than $400 of the tech's time on two visits just trying to find the culprit and would very much appreciate some direction.
Lastly, yes, all items have been removed from trunk and glove box just in case.

 

I had a similar type noise from my 90 xj6. Mine was under the hood and it turned out to be a blown exhaust manifold gasket letting the exhaust out(i acted like a reed in a saxaphone).As your noise seems to be coming from the back of your car i would check the exhaust system from the cats back(you might find a leek)

 

Wow .... I never knew that Jaguar use Welsh veggies as baffles in the exhaust system, lol

(Sorry)

 

I've just run my fingers over a note pad, as you requested. Ughhh not a happy chappie.

This 'sounds' like a resonant 'sound' effect from what you describe as being driving conditions led.

Have they checked any exhaust heat shields that may be welded to the exhaust?

Only mention this because on my XJ40 I have a similar set of symptoms, but at least I know the cause of my sound.

 

Have you had the techs try driving the vehicle while its is on the lift off the ground to maybe replicate the noise & may be simpler to narrow down.

 

Update! Finally got under car myself (had to park over a ditch to get enough clearance) :-) and found two culprits. One was a metal clasp which is part of the emergency brake cable. It was clanking against the frame. The other was a loose bolt meant to hold the front end of the muffler where the prong sits inside a rubber bushing. It was only noticeable when pushing finger between bolt and receptacle and shaking the bolt. I tried to upload photos but was unable.
The solution was to take back to dealer where they applied a sturdy foam padding to frame so brake cable would;t clang, and they tightened the muffler attachment after applying some thread lock to the bolt.
Thanks to everyone for the suggestions. Car is now quiet again...well, at least until I hit the gas :-)

 

Any idea how to access this metal clasp on the parking brake cable? I think maybe this explains the clicking/clanking sound I have when getting on/off the gas and making abrupt changes in acceleration (high "jerk").