2012 m3 misfire codes

[kninjak]

Hello.
I have 2012 M3 since 2013. Bought the car at 9500 miles now at 79k updated the tune in 2015 from evolve for test pipe and cold start delete and since running fine until last couple month.
I had read code through obd hand hell code shown p0301. I had it cleared a couple time and it came back after couple months , so last month i swapped the coil from 1 to 2 to see if the coil is the issue and I also changed the spark plug in cylinder 1 just in case the coil foiled the plug.
I finally got the evolve software updated and read code. I got 20 code in memory. currently there is not engine light on.
The car start rough and once I restart it goes normall, it has rough start once every 2 week.
I am attaching the code from evolve software

[Three Pedal Steve]

There is another misfire thread going now:
https://www.m3post.com/forums/showth...1465500&page=2

One poster suggests that coils and plugs must be replaced together and that mixing them causes both to fail.
Overall there seems to be increased forum chatter about misfire issues recently.

[kninjak]

I did swap the coil from 2 to 1 and changed the spark plug in cylinder 1, to see if it’s bad coil in 1 should go to cylinder 2 but the issue still remain in cylinder one , guess need to buy new coil and spark plug for cylinder 1

[Three Pedal Steve]

Originally Posted by kninjak

I did swap the coil from 2 to 1 and changed the spark plug in cylinder 1, to see if it’s bad coil in 1 should go to cylinder 2 but the issue still remain in cylinder one , guess need to buy new coil and spark plug for cylinder 1

Not sure about validity of that poster's comment. In fact, I have to question it; because dealership and independent service shops both routinely do the coil/plug swap for diagnostic procedures.

[fs34]

Every time I see these threads I recommend you check your grounds.

It looks like all cylinders are affected based on your scan output. This could be DME related but hard to tell based on your scan.

I’ve had a couple of grounding problems. First was entire bank 2 misfires because I didn’t tighten the ground good enough when I replaced valve covers.

Second was harder to find and caused 6&7 misfires. Previous owner had TBAs replaced and the shop didn’t bolt the engine harness down, there are integrated grounds there that the ignition system uses. I didn’t see this but the dealer eventually found it.

Good luck with your troubleshooting, I hope it’s a simple fix.

[Zark get a spanner]

I used to get misfire codes on 1 and without any other code. If I run the car, there is nothing, but idling will, restart the car, it was normal, only low rpm I got the codes, and have to restart the car.

Front O2 sensor gave me a black week.
I exchanged parts one by one from 1 to 2 by my hands, lots of parts, but codes were still on 1, spent me a week. Finally I put the sensor1 to 2, put the sensor2 to1.The codes went to 2. I replaced the two sensors, my car revived.