So I had this gremlin in my wife's BMW 330i for at least 4 years. The car runs great but once in a while you would start it in the morning and the engine would sound rough with some shaking. After few minutes it would go back to normal and I wouldn't see this problem for months.
Few weeks ago we had a snow storm and while snow blowing the driveway I had to move the car. After moving it, the next day I got the same misfire and it got me thinking that a lot of times when I had that misfire, I did something else to the car, like drive in/out of the garage (very short operating time as well).
So what would cause misfire like that, several hours (12+) later after very short run?
In the past, I've simply ignored this quirk, but lately been trying to see if I can understand it. When it happened once back in the fall, I pulled the engine cover off and disconnected ignition coils one at a time until I discovered that cylinder #4 was the one that was misfiring. When it happened this time, it was 5 am and I was going to the airport, so didn't have time to see if it was the same cylinder.