08 RZR 800 Sputtering loss of power PLEASE HELP

I have an 08 rzr 800 around 3500 miles. It rides fine for about 10 minutes then starts to sputter and lose power will sometimes ride fine in between sputtering at different rpms but not for long. I am going to clean the gas tank out tomorrow. Any other suggestions I am kind of lost here. :redrzr: