I got the codes P0300 and P03001. I changed all the ignition coils and all of the spark plugs. I checked the coolant and oil. I chained my air filter and my thermostat. The check engine light went away came back blinked for a few and went away again and came back on. I took it back to mechanic and he said nothing is wrong with it and he isn’t to sure why I got the same codes and the light came back on for. Any suggestions? The light stays on and only blinks when I drive fast.