Hmmm. Well, I can't think of this part you are talking about from the top of my head (unfortunately), but remember not only to practice slowly, but at like 5 different speeds (including up to speed)
Also, make sure you can play it hands separate with the metranome (once again, i don't know which part this is, so if they are grace notes, this would be hard to do).
There's usually a solution to every problem.
What is giving you the trouble? (specifically, what notes do you play, and what is the difficulty?)
Practicing in crazy rhythms helps big time. (triplet whole, triplet whole, etc)
Unfortunately, I don't know your problem so I can't give good advice, but I am pretty good at solving technical problems.