I posted this on the cx-9 community as well, but wanted to share here just in case someone might have answers.

I am at a loss and hoping someone here can point me in the right directions. I bought my 2018 CX-9 (sport model) with about 45,000 miles on it back in February. Has been a great car, drives fine. I got a free oil change from the dealership I bought it from over the summer when it was time to get it serviced. The very same night, the Check Engine Light came on and I took it to my local mechanic. The code was for a Cylinder 1 misfire, P0301. They changed the spark plugs and coils and I was on my way. A month later CEL pops back on again. Same exact code.

I took it to another local mechanic who I trust, and they changed out the plugs and coils. Light stays off for another few weeks until it doesn’t. I take it back to the same place, they replaced it and said sometimes it could just be a faulty coil. When it happened a third time a few weeks later, again same code they kept the car and tested everything they could. They couldn’t find any other issues with the car.

As a last resort I took it back to the dealership which I did not want to do. They gave me some bogus fix, and said I needed to replace the entire harness, a $2K fix. They showed me some wires, and pointed to that as the problem. When I took it back to both mechanics they laughed, and said those wires are how it rolls off the factory and the dealership’s service department was either incompetent or just tried to rush me out without looking at anything. Both independent mechanics looked at the car again and still could not find anything wrong with it.

My original mechanic drove it around and said it drives fine. He reset the battery, and light stayed off for 4 weeks. Just before Thanksgiving the light came back on as I was going down my driveway. I made sure with my mechanic it was good to drive. The morning we were hitting to road to drive from NY to PA light was off when I turned the car on. We made our trip there and back with no CEL light.

Then on Tuesday 11/28 my husband was running errands around town and light randomly popped on in the middle of his drive on a local road going about 45mph.

We have essentially been dealing with this since the summer time, with no solid solution. No one can find anything between two different mechanics at two separate shops. I’m hesitant to take it back to the dealership for an outrageous fix that wasn’t even necessary in the first place. Has anyone dealt with this random cylinder 1 misfire code? Would really appreciate any insight.

Thank you in advance for any responses.