Rode well for first ten miles then it spit and sputtered. Changed the plugs and it ran slightly better. My brother took it out the following day for six hours and it ran great for him. He filled it at the same gas station I used and parked it. I took it out the following day and it was the same story. Ran good for half the trip then spit and sputtered the final miles. Is this a bad gas issue? Or should I look for other causes?
