I have changed the plugs as well. It only does it under load it seems worse at lower speeds maybe 20 to 30 percent throttle but it does continue all the way through full throttle. It has never thrown a check engine light. I have taken it to a BMW specialty shop they couldn't get any codes from it. I hooked several other scanners up to it and it had no codes. I took it to BMW they were able to get a misfire code on two cylinders I don't remember what cylinders it was. They didn't want to go any further until I spent almost $1,000 with them replacing the coils and plugs I had just replaced because I didn't buy them from BMW although they are the Bosch coils. I have been driving it for a while. Still never throw. A check engine light. We recently just got a new snap on modis ultra scanner. I hooked it up and it is showing multi cylinder misfire. It shows cylinder 1 2 and 7. It also has a code 2a17 dmtl system error. I have been told possibly mass airflow sensor. Eccentric shafts, PVC system problems. We did also replace PVC valves. Not really sure where to go from here don't wanna just start throwing parts at it. I cleared the codes and drove it for a couple weeks Hooked it back up and it's not showing any new codes it seems to take quite a whole for it to throw the misfire codes although the misfire never stops.