Rattle Under Front Passenger Seat

[mcoomer]

My wife's car has developed a rattle under the front passenger seat. It only occurs at freeway speeds but when it happens it's like fingernails on chalkboard while rubbing jalapenos in your eyes bad! I've got the front passenger seat out, pulled the rocker and b pillar door trim, and can get the carpet up a bit. I figured I'd find a loose coin under there, but I don't see any debris under there but dust. I stuck a borescope in there though and saw something interesting. If you follow the vents from under the passenger seat forward, there's a seam where you can remove them and another piece that goes forward from there and up under the center console and dash. The borescope shows a flange fitted over a threaded stud, but no nut on it. I can't see the far side yet to see if there's another stud. If anyone has been under the carpet, do you know if this should have a nut on it? I don't see a loose nut under the carpet, but I can't see everywhere. Thinking about it, that's roughly the area I hear the noise, so I wonder if I'm hearing the nut vibrating on the floor pan. I do know it's driving me crazy.

223455

Thanks,
Mike

[mcoomer]

Checked with the dealer finally, and found there was never a nut on that stud. Dug around under the carpet as best as I could and never did find anything. Pulled the felt insulating pad from under the car and didn't find anything loose. Played a 60Hz test tone through the car speakers and found a rattle in the drivers side door, and read deck near the speaker grille. Never did find anything that appeared to making noise in the area of the passenger floor. Put the b pillar and rocker trim back in, reinstalled the seat, and the noise has decided to fix itself. Guess I should be happy, but my experience is that when a problem just goes away, it will come back at the worst possible moment. Oh well...