New member here. Not sure if I am posting to the right place.

I have a 2011 mini cooper 1.6L base model. I am getting P0301 Cylinder 1 misfire. Swapped spark plug, coil, fuel injector. The code stays with Cylinder 1.

Reading other posts on the site that suggest to clean the carbon build up. Opened the intake manifold. It looked like the fuel injector is actually outside the valve in this model. The intake valve is clean. Did a bit cleaning anyway. Bottom line: problem stays with cylinder 1.

What I did notice is: I can hear popping sound when I run with all 4 cylinders. The sound like a Harley's motor cycle. Not as loud and only occasionally. If I unplug the spark plug wire to cylinder 1, the engine runs normal on 3 cylinders. I haven't done the compression test, as I don't have the equipment. I hope the symptoms here can give some clue. Any advice from the experts here?

Thanks much

 

did you clear codes after each swap?

 

Moving you to the Gen2 Stock Problems/Issues section.

 

Yes, I did clear codes each time.

I just did the dollar bill test and confirmed there is suction at the tail pipe. Which means the issue is a leaky exhaust valve.

Now the question is: how much effort is it to fix the leaky exhaust valve. :(