When I was driving today, I got off of the highway and noticed that my car was struggling a bit. At first I was thinking that it was having trouble getting into gear. It seemed to be a sporadic loss of power but not so severe that made me too worried. I got to my destination alright.
Later on when I started driving home, I felt the same slight loss of power and the check engine light came on. I got on the highway and started going 65/70 mph. At some point I notice the temperature of the car go low, to the left of center, and I think my thermostat is broken again (I’ve replaced it twice). I had 9 miles to go and I thought I would make it alright but I was wrong. A few more minutes in I started hearing a loud engine noise and smelling gas. I pulled over and the spark plug had shot out of the housing, leaving the nut still threaded in the engine. The wire was slightly burnt. I had my socket set and a spare plug so I removed the nut of the broken plug and threw another plug in there.
I hopped back onto the highway to go the remaining ~2 miles home. The car seems to be running okay now and I get back up to 60mph. Now a minute or so later I see another dash light come on like (!) and see my thermometer is all the way in the red. I am like 30 seconds from the exit so I keep going and as soon as I hit the ramp and slow down, my temperature shoots right back to the center.
My check engine light is still on and my temperature is right where it should be when I drive on side streets under 30 mph. I read the code and it says P301 cylinder 1 misfire. I have not leaked any coolant or oil and my car usually doesn’t.
I’m not sure what to do here… I don’t know if this is related to my cooling system, a sensor, or something with the engine itself. I also don’t know if I did serious damage to my head gasket while I was red-lined for a minute.