2021 Mazda 3 starting/idling issue.

Hey guys,

Looking for some advice regarding my 2021 Mazda 3 with 90000km.

Two days ago I went to start my car before leaving for work and noticed it struggled to start. I drove to work with no issues, but did notice flutter on the rpm’s and a mild shake when idling.

My car had the same stutter start when I left work and the same idle issues with normal driving.

The next day I went to start my car to go to a massage with the same issues persisting. I then got my massage and when I went to leave it had a really hard time starting, cranking over multiple times before sputtering to life. I drove it to get the battery tested and was told the battery is fine. Right after getting the battery tested it then threw a P0300 code, random engine misfire. I drove it home, parked it and made an appointment at my trusted mechanic.

I went to start the car later that night and it failed to start on the first cycle. Second cycle is fired right up, but idled rough.

A few things I’ve noticed:
•Difficult cold start and rough idle after rpm’s settle.
•Idling at stop lights produces a very minor flutter and an associated shaking.
•Starts easier after initial cold start.

The soonest the garage can get me in is in a week. Anyone have any thoughts?