Treadmill slowing down and speeding up then the belt stops Sole F63

It is a Sole F63 that was purchased in 2008. I replaced the belt about two weeks ago and it worked great until all of a sudden it started to do some hesitation. It is like the motor stops and then starts real quickly. This happens whether I am on the belt or off the belt and it happens whether I am at .5 mph or 3.5 mph. Eventually, the belt stops completely. If I run it at .5 mph and get right down by the motor, I can hear it cutting out and back in again. When it does this, it makes a soft grind noise when it cuts out and when it kicks back in again. Almost like a sandpaper noise. I have checked the belt adjustment and lubed. I have checked the speed sensor adjustment and made sure the treadmill was plugged directly in to the wall outlet. Could this be a bad motor? The motor is supposed to have a lifetime warranty but I figure Sole would want to send out a technician that would most likely charge a service call and labor,

Any guidance on this would be greatly appreciated.
Thanks!