Hello folks, It's a pleasure to join you fine people here and happy to be a part of the family...
So here's the problem:

04 530i w/ 40K mls , auto trans.

In (P) tach showes a little twitch. Even warm, in all conditions.
In (D) normal during a constant speed with foot on the gas. Same twitch is present but at higher RPM.
In (D) normal during coast from about 40mph to about 20mph, tach twitches with higher variance and i can feel the car 'surging'.
In (D) sport mode same as above.

Dealer "could not duplicate". 1 attempt.
I hope this is not normal.

Thanks in advance.

 

I had a similar issue in (P) though not the issues you are experiencing in (D). Dealer could not replicate either even though it was quite evident to me. I think mine was purely the tach and not the engine. In my case the engine felt quite smooth and there was no corresponding vibration or up and down fell to the revs. At a later date had a software update and the twitch is gone, rock steady now...