Initially I cleaned the solenoids, checked that they were functioning, then replaced the seals and finally replaced the solenoids. I am now fairly sure it is the eccentric shaft causing my problems and I have nearly convinced myself to shell out the $5000 AUD or there abouts and replace them and the intermediate levers (and any other parts that should be replaced in the process).

Cool, yeah I wonder if the pitting is caused by the solenoid making the cam position get stuck in one extreme position. I have always had a little bit of surging in first gear when just giving it a little gas, like driving through a parking lot for example, but nothing like this. As soon as that CEL starts blinking I stop driving and restart it. Gonna pull the solenoids and see if cleaning helps before I disconnect the solenoids.

It sounds like yours is going into a default mode where it uses the butterfly instead of the eccentric cam. In that case it will idle at 700 instead of 600. But you really won't notice much difference in driveability.

I'll try to report back after I get those solenoids cleaned up. :)

Yeah that's a hefty price tag. I'd try replacing them myself before shelling out that kind of money. I've done nearly everything else on these cars, can't be that hard. This is my third X5 so I definitely know all their trouble spots by now. This one is new to me because I had the M62 in my previous E53`s.

Maybe I'll stick a camera in that valve cover and see if I can see any pitting. I'm wondering if this might be an electronic gremlin. I don't really trust BMW mechanics, there are a lot of half ass RnR guys who don't really know what they're doing. I've learned that over the years.

As some guy once said, "trust, but verify" :)

Check out a guy on YouTube called bmw doctor. He's got a lot of videos on programming. He talks a lot about the rough idle issue on the N52. He used to work at a dealer so he knows all the secrets. The N 52 has basically the same valvetronic system. He says the only way to fix it is to get the new updated vanos solenoids and then update the firmware. Make sure to use the plugs with four electrodes and that will fix it permanently. I have a feeling the fix is the same here. He says that the original vanos solenoids are not designed to work with the new updated software and they will fail. Also if you're not using the right plugs it will cause your coil packs to fail.

Just search his channel for rough idle, he's got a few videos on the topic.