misses in a long hard pull

Hello all. Have a 2014 Rancher that I bought in 2016. Had 2 miles on it. Now has 196 miles. had it serviced at 100 miles. Has always ran fine up to last weekend. going up a pretty long hill in 5th gear and near the top it shut down then spit and sputtered then back fired. I stopped and it idled perfect. headed back home , about 3 miles, and it would do good until I got in a hard pull in 4th or 5th gear. Any help is appreciated.