Bryan Kuban

I have a 2013 Fusion 2l eccoboost with 62k miles on it. About 5k miles ago I started to get a rattle coming from the trunk. I have stripped everything out of the trunk to try to find it including the spare tire with no luck in finding the rattle. I have put a piece of clot over the torsion bars for the trunk with no luck, I have completely taken out the back seats, I have had my son crawl in the trunk and look for it while I am driving with no luck. I jacked the car up to take a look underneath and pushed and pulled on everything without finding anything loose. It only happens at speeds slower than 30mph. It is driving me bonkers. Has anyone had this problem? If so can you please please please help.