Something is rolling under rear passenger seats

[Acisplat]

For the past couple months, I've been trying to figure out what is rolling underneath the rear passenger seats of my early 2023 5-seater Model X, and trying to get the service center to find it and remove it.

It sounds like a small item rolling around, and ping-ponging from left to right when I make turns with the car.

The noise only happens about 50% of the time while driving, which makes me think it's getting stuck in a crevice and then having the brakes dislodge it while driving.

I took it into a service center last week and despite having it for hours couldn't reproduce the noise, or find it. About an hour after picking it up, it made the noise again, and now I have to wait for a service appointment in late June.

Is there any easy fix for this, or something that I can do that will push the service center in the right diagnosis direction?

 

[mbp11]

I assume that you have opened up the back trunk and then the secondary back trunk (in front of the main deep trunk, but behind the back row of seats)) and taken out all of the items there. I had my 2018 MX for 4 years before I found out that there was a forward storage space in front of the back trunk.
I felt pretty stupid.

 

[Acisplat]

I assume that you have opened up the back trunk and then the secondary back trunk (in front of the main deep trunk, but behind the back row of seats)) and taken out all of the items there. I had my 2018 MX for 4 years before I found out that there was a forward storage space in front of the back trunk.
I felt pretty stupid.

I've checked and all the rear storage is empty, I wish it had been that easy though

 

[Ostrichsak]

It may not be under your passenger seat but in your passenger door. There's a door limited connector thingy that can break internally. This is the part you see that prevents your door from going past a certain point between the front hinges. Often times, if this breaks, your door also will not sit at the detent positions partway open that allow it to stay steady at a couple of predetermined distance of being open. If your passenger door doesn't stop at these obvious detents then this could be your issue and the part for that is rolling around inside of your door. Don't ask me how I know all of this.

 

[mbp11]

It may not be under your passenger seat but in your passenger door. There's a door limited connector thingy that can break internally. This is the part you see that prevents your door from going past a certain point between the front hinges. Often times, if this breaks, your door also will not sit at the detent positions partway open that allow it to stay steady at a couple of predetermined distance of being open. If your passenger door doesn't stop at these obvious detents then this could be your issue and the part for that is rolling around inside of your door. Don't ask me how I know all of this.

Good suggestioins~

 

[Acisplat]

It may not be under your passenger seat but in your passenger door. There's a door limited connector thingy that can break internally. This is the part you see that prevents your door from going past a certain point between the front hinges. Often times, if this breaks, your door also will not sit at the detent positions partway open that allow it to stay steady at a couple of predetermined distance of being open. If your passenger door doesn't stop at these obvious detents then this could be your issue and the part for that is rolling around inside of your door. Don't ask me how I know all of this.

It rolls around from the extreme left side of the car to the extreme right side, is it possible that could get under the seat assembly?
I'm not sure how the falcon wings work

 

[carlrbrugger]

This may or may not be related, but when I was installing an accessory in the back of the console, I had the passenger seat moved all the way forward and I noticed a small, silver ball (bearing?) about the size of a bb laying in the track. I only had 200 miles on the car at the time, so I never noticed the sound of it, just happened to see it. Probably got away from a worker during assembly.

 

[geordi]

Removing the floor is easy, and then you can dig around for whatever is down there. Start with the two door sills, pull straight up to remove them. Then you should see the trim pieces at the corners, unscrew / pull up (it's been a while since I did this on mine but it was pretty self-explanatory) and then the floor panel itself in front of the bench will lift up. There's nothing really holding it down other than gravity, now you can have a good look and see!

The foam blocks aren't glued down, and the back half of the floor is the same - just lifts out once the wall trim is pulled up / away from the edges. Look at the Rich Rebuilds videos where he disassembled a flooded X to see how to do it.

Five dollars says what you hear rolling around is a 10mm socket.

 

[chuck531]

All of a sudden I started to hear the marble sound rolling around under the passenger seat, I tried to ignore it but eventually it started to drive me crazy. Logged onto this site and explored all the remedies...took the seats out explored all the channels under the seats but no luck, attached a plastic hose to vacuum poked around no luck.
Just to cover all my bases I shook the vent under the seats and heard the rattle...tried the vacuum with small hose attached no luck but finally jury-rigged flat plastic drain cleaner(Home Depot) with a sticky pest strip on the end. I inserted the gizmo into vent, drove around for 5 minutes didn't hear the rattle anymore pulled it out and there was the acorn.
Thanks to everyone who posted, it gave me a starting point, I hope my remedy will help someone save time and money.