So was running my car on 93 octane. Then for 2 weeks i switched to 110. Had about 1 and a half gallons left of 110 in the car and put 8 gallons of 93 in the car. As soon as I left the gas station the car started missing and running lean. Changed the plugs. Oxygen Sensor looks ok. Reset Computer. Checked Cap, Rotor, and wires which were all ok. Drained the tank all the way and put 5 gallons of 93 from a different gas station and it still runs the same. Fuel injectors?

 

Sounds like to me that you had moisture/water in the gas and since gas is lighter than water, may still have water still in the bottom of the tank.

Could also be a coincidence that some thing is wrong with you timing/ignition.