It you talk to a lot of authors, you’ll know that the biggest problem most have is right at the end of the book. More specifically, at least in my experience, is just before the end of the second act. It’s where a lot of people get into trouble.
I will admit, I’ve had the same problem, especially in the past when I didn’t heavily outline like I do today, but now, it’s a whole lot better. I don’t slow down at the end, I accelerate. Now, I sprint to the ending.