Yesterday, after traveling about 75 miles, the sled started hesitating and backfiring when accelerating. If I accelerated very slowly, and smoothly, it barely did it but I couldn't get over 35 MPH or else it would start to hesitate. The fuel level was full when we left the house and was down about 4.5 gallons when the issue started. I filled up at a gas station and the issue went away immediately until about 60 miles down the trail when it started again. This time it was slightly worse and had difficulty getting the sled to travel over 20 MPH. Up hill was even worse... After a bit of research I narrowed it down to the fuel sock, or possibly the fuel pump. I took the tank off and removed the fuel pump and the fuel sock inside was slightly dirty but no where near where I would have expected if it was responsible for the running issues. The local dealership had a fuel pump in stock and I was able to switch it out. It was immediately improved. Looks like the fuel pump solved the issue. The only issue I had, while re-installing the new fuel pump, I didn't get the o-ring seated properly and I had the sled half way back together when I put gas in it and it started pouring out all over the floor... Super frustrating and made a HUGE mess. Was able to yank the machine outside before too much gas leaked on the floor. I then tripple checked it before I re-installed it in the sled. If you are replacing a fuel pump, put some gas in the tank and check to make sure the o-ring is seated properly before you put the machine back together...