I change my mr bov to the stock one, use the car for one day no problem. Then go to gas station an fill up the tank with 93 octane. At the moment i leave the gas station i turn on my car and the a/f ratio don't raise from 10.1 then after 15 seconds the a/f ration began to raise to 14.5. I start moving. I do a full stop in a light when i began to move i 1st. gear i have to brake and the car idel for a second and the p0300 appear. I turn off the cel with a scaner but again but this time in the highway the code appear

Can this could happen for a bad gasoline ? I am going to install the mr bov again just in case. And i will fill up again the tank in another gas station to verify if this goes off.