I've been driving my 05 around and noticed that sometimes, usually when making a turn at a light from a dead stop, I will hear a sound behind me that sounds like a thump or thud. It sounds like if you had a heavy object in your trunk and took a turn where it would bang off the side. It's pretty loud, can hear it easily with the radio on. It happens on the left side if I turn left, and it happens on the right side if I turn right. I do need to note, that it isn't ALL the time, just sometimes on turns.

I searched, and the only thing I found were some things on the seat clunk noise. I'm not sure if it's the seat moving, because I adjusted it and it really sounds like it's coming from behind me, not below me. Another reason I don't think it's the same thing is because it doesn't make a metal sound at all.

Also - There is nothing in the trunk, or the compartment behind the seat and the spare is not loose.

Oh yeah, it's an 05 AT Enthusiast if that makes a difference.