I have a 2012 E350 Sport (effectionately known by family and friends as "Lord Vader")

For the second time I am having an issue with the rear spoiler where it will not stay flat on the trunk edges. I am bringing it back to the dealer, again for the second time, but this time on the opposite side. If anyone else is having this issue and found a solution please post. Thanks!

 

Replace it completely - I posted in another thread just a few minutes ago. The glue or tape isn't meant to shape the spoiler only affix it to the trunk. If it lifts and keeps lifting your probably in need of a new spoiler.