you might search this group for similar post, I think others have discussed
something like it.
I had a creak really, not so much a rattle...only in cold weather over
washboard surfaces and at hiway expansion joints. As it disappeared over,
say, 50 degrees, I ignored it.
I did mention it to the dealer when in for routine maintenance. I cleaned
out the car, bins ,and truck just in case they would look for it. When I got
my car back, the mechanic complained I had too much loose stuff in the car
to chase a rattle! I had a small stuffed animal on the dash!....Well, low
and behold, the rattle was gone...they fixed it though no mention of fix is
on the repair order..........I think some suspect windshield/dash panel fit.

<mbleisch@gmail.com> wrote in message
news:1173804418.840330.159760@s48g2000cws.googlegr oups.com...
>I have an 06 Sonata LX and recently I have noticed some (extremely
> annoying) rattling noises coming from the front passenger side area.
> It only occurs when I hit bumps, and in New England weather, the frost
> heaves are everywhere.
>
> I am not sure if it's the speaker in the passenger door, the actual
> passenger seat, or the glove box. My suspicion of the passenger seat
> is because the noise becomes quite faint when I have a passenger, and
> only more noticable when I hit a bigger bump in the road. My
> reasoning for the glove box is because it seems to become louder when
> I drive with it open. The speaker is a silly thing to think of, it's
> possible, but why after a year did it come loose?
>
> Hyundaitech....any clues?
>
> -M
>