I suppose I am not the only writer who comes here. Does anyone else have the massive problem of stalling right before the climax of the story? Do you ever reach a point where you want to give up? Does anyone have ideas or exercises to prevent this mental block?

Every writer runs into writer's block. You either have the ideas or you don't. There's no preventative measures, and there's no magic trick to create inspiration. If you aren't already doing it, outline an entire story before starting. There are few people who can just pick up a pen and go.