Some pepper varieties are finicky. It's not a matter of having bees/insects and such for pollination because peppers, like tomatoes, are self-pollinating.
Heat is a factor though. Although the plant itself grows well in high heat the pollen becomes non-viable at higher temps. You might try "thumping" the flowers in the mornings, Lee Anne, to help with pollen transfer before the temps begin to rise.
I always recommend to feed peppers a breakfast, lunch, dinner regimen. Feed/fertilize at plant out time, side-dress when you see flowers coming on, and one last time towards the end of the season to help the last of the peppers gain in size.
Lastly, the only thing I can think of is your sandy soil probably heating up a bit too.
Hope you get some peppers before your cold weather begins!
Shoe
