[Adrianhe]

Hi, about two weeks ago I put on a Corsa catback exhaust on my 2018 Brz without any having any issues. After about a week of installing the catback I started getting CEL Code P301.

The car only has 17K miles on it so I'm a little shocked if the spark plugs or injectors are going bad.
The car starts rough on cold starts but after 10 seconds of warming up the car run smooth. The code goes away if I erase it with an OBDII but usually comes back after having a cold start.

Two days ago the car started over heating. Sometimes the car overheats when driving but after 3-5 seconds of the overheating light blinking; the temperature drops back to the middle.
Both radiator fans kick in and the LH one is always on when in idle.

Did anyone else had a misfire when changing their catback?