| N52 idle race/surge on cold start
I have a 2006 530i with 133K miles. Have noticed recently that on a cold start (warm or cool, dry or wet weather, happens in all), the first time I engage the transmission in either D or R, doesn't appear to matter, I get an idle race/surge. Very brief, disappears once I lightly press on accelerator and car moves. I also get the occasional check engine light but not specifically associated with the events I just discussed. Have never replaced the pre or post cat O2 sensors or rebuilt the CCV system.
Anyone recognize the symptoms? Suggestion is it could be a vacuum leak, perhaps in the CCV system. Looking for guidance on diagnosis and where to start the remediation process. | 
Linear Mode
