Raddle Trap

I would say the problem is that you are driving a prototype Saturn, immediately trade in your car for a production model. Saturns werent made until 1990. ;-) JK

two most common rattle problems are the rear seats arent fully latched when upright and there are two thin cross bars in the trunk that can rattle especially when in reverse or idle. Pop the trunk and look up in the top of the trunk. You can put some foam to separate the cross bars so they dont rattle.

marx404