Bad fuel. I stopped here and paid cash for the on my way to page and Bryce canyon. Check engine lights for a knock sensor and oxygen sensor came on. Fueled up about 250 miles later (can normally get closer to 325 miles) and was nearly empty. Lights were reset at the same time as next refuel. 2 days no lights. On my back down I tested my theory and got fuel from the same pump even. Sure enough check engine lights returned. Again got better fuel and turned off the Check engine lights. Now a week later and an extra full up no lights on ~M