X2and4X

so this weekend on my way to omaha from des moines. just filled it up when i got to a 1/4 of a tank. Then about 50 miles down the road i stopped to take a leak . got back on the road about a mile down the road i noticed the check engine light. i pulled over checked it. everything was in order. started it back up it was running great light was still on. drove the 15 miles left to omaha. then a friend and i took it to advance auto to have the code read. they said it was a o2 sensor on bank one. he must have cleared the code b/c its not on anymore. could bad gas have tripped it up. or should i just bite the bullet and face that i have a bad sensor?