Passenger seat noise.

Does anyone else have a noise problem with their passenger seat? When driving it vibrates. When I tap it with my hand I can hear a vibration. When I tap the drivers seat, it does not make any vibration noise. Visually looking at the seat, I don't see any loose parts.
 
Does anyone else have a noise problem with their passenger seat? When driving it vibrates. When I tap it with my hand I can hear a vibration. When I tap the drivers seat, it does not make any vibration noise. Visually looking at the seat, I don't see any loose parts.

I have a similar intermittent noise problem - it's extremely annoying and seems to appear under the following conditions:

1) I've spent all weekend working on my car.
2) The spring yardwork isn't done yet.
3) My wife is sitting in the passenger seat.

:rlaugh: