My 2011 BMW X3 xDrive28i shakes for a few seconds every time I start it up. HELP!!!

[alifeili]

I have a 2011 BMW X3 xDrive28i with 49K on it. For a while now every time I start up the car it kind of shakes and the RPM slightly dances up and down for about 5 to 10 seconds before everything gets smooth again. I thought it could be the spark plugs so changed all 6 of them with Bosch double platinum spark plugs but that didn't fix the problem. When I was changing the spark plugs I also checked the ignition coils too and they physically looked good, but i'm not sure if there are some internal damage that I was not able to see.
Does anyone have any idea what may be causing this or how to find the issue? The ignition coils are pretty expensive so I rather know for sure that they're the culprit before I change them out.

I really appreciate your help and advice.


Thank you

[my1stE30]

..... if you have any vacuum leaks in the engine then the condition you describe will occur. A smoke test will indicate location of leaks