In the last 2 weeks I've noticed a surging of the RPM at idle. I can feel the car shudder and the RPM will fluctuate up and down a few hundred RPMs. This will come and go. I have a 530i with the N52 engine and 88K miles.

I've read about the engine idler going bad.

Any ideas?

 

Have you replaced he battery? That or the alternator would be my immediate guess....start with the battery.