Good grief. What about pulling the existing one off and just replacing the tape with something that's actually worth a chit? If you get another emblem, apparently, you're just going to get more chitty tape, too!
It's probably from the same batch of adhesive they used on those wheel weights that kept flying off everyones wheels.

If the adhesive is old or from a bad batch, there may be hundreds of emblems in the system that will eventually do the same thing. So if the replacements also fail, just replacing the tape with some good 3M exterior grade molding tape may do the trick. But, if I remember correctly those emblems aren't flat; the emblems and the tank surface have compound curves that need to match exactly. If the emblem isn't positioned correctly, the adhesive is much more likely to fail. If one end of the emblem is lifting up off the tank, that's a good indicator that the shape of the part is wrong or it was applied in the wrong location.
Of course it could also be a lack of proper surface preparation and adherence to installation process instructions. I remember having issues in the auto plants whenever people decided they knew more than the engineers and started shortcutting the process.
Jerry