Today was my second visit on my rattle. First time they could not reproduce it. I had one day when it was solidly rattling so I took it into the dealer so the service writer could at least verify that it existed. We booked my second appointment for today.
Of course - today was a non-rattle day for the car. It didn't rattle the whole drive to the dealership. They called me at 4PM to say they couldn't get the car to rattle - please pick it up.
I drove it off the lot and the rattle was there. I did a 180 and got a tech to drive with me. At 3800 RPM it was constant. He did the pat-and-poke routine and identified it.
The passenger side has a small compartment for storage beside the engine. The lid to the compartment was rattling. He could stop it by holding on to it.
You can see the offending rattler in the pictures.
It goes back on Monday for the fix.
DF.