Guys I have been having this problem since a long time and I can't find a solution to it, so I thought post my question here...

I have a '09 520i that has about 86000km that's running good overall except for one little thing thats bugging me...

Whenever I stop by a traffic light (often with AC on) I feel the car shaking and vibrating, and then about 30 seconds into it, the car starts to shake really violently and RPM needle goes crazy up and down, and you can really feel the whole car vibrating. After about 3-4 seconds of this everything goes back to normal with just the "usual" hard idle that most e60s have. No engine fault messages though.

I asked several repair shops including my local BMW dealer and nobody has an answer!

I hope someone here can help with determining the problem with my car.

Thanks,

[font="'Comic Sans MS"]post a video of it happening?[/font]

That kind of surging is often related to the AC - get your AC system checked out by a specialist. Could be as simple as a low refrigerant charge, or a fried temperature sensor.

It sounds like it may be that the AC system gets too hot while idling - or thinks that it does, and causes the engine rpm to go up in an effort to cool things off.

I have a 07 550i, at idle with the A/C on, the car idles rough... As soon as I turn the A/C off, the engine purrrrrs perfect? I've notice the RPMs are higher with the A/C on... When I turn the A/C off and run the RPMs up to where it is with the A/C on, I can feel the rough idle.

I've replaced the plugs... Any other ideas? Thanks in advance!

I think just from the AC compressor kicking in. Happens with my 08 528 and used to happen with my 03 Tahoe too.
Wasn't a violent shake...but definitely able to tell the additional stress on the engine.

If it's that bad, you should have at least pre-coding. Get it scanned- it's emmisions related within all likelyhood. There are quite a few adjustments made in that system when the air goes on, including increased fan speed, idle adjustments (IAC manipulation) and other goodies. I would wager IAC valve, possibly a bad temp sensor, but get your codes read first.

I experienced the same on my e92. After about a week at the dealer, they were finally able to duplicate the issue, they said it was due to a misfire on one of the Spark plug ignition coils. After they replaced the faulty coil, the issue never returned. Sounds like your issue may be the same.

damn that is such an annoying issue to have! The spark plug coils does seem like it would remedie the problem

Don't think he mentioned it throwing error messages. And any code reader isn't going to give him proprietary codes.

That was my exact thought.. replaceing the coils. I'll keep everyone posted if replacing the coils resolves my issue.