Rough idle at start up, turn off engine and restart then idle is smooth

[ac427]

I have rough idle at start up but if i turn the engine off and then back on it is ok.

I've seen mentions of this elsewhere but without an actual answer to the cause.

I have no DME error codes.

Has anyone else experienced this type of fault?

[ChapterM3]

Can you provide a video and more information about your car? What mods, maintenance, etc. That will help the community help diagnose this further

[ac427]

Sure. E46 M3 186k miles running CSL software and CSL airbox plus CSL cams. As it has done for around 8 years.