jlp93

It happens at low speed, especially when simultaneously deccelerating and making a turn.

Sounds like an empty plastic soft drink bottle bouncing around rapidly inside the rear fender.

Any ideas?

Bali26

There must be an empty coke bottle in your trunk....

Have you checked the 2 empty spaces on both sides of the wheel well? You may need to put your arm in it to feel around. You could have somebody sit in the back seat and attempt to find out the source...