I picked up the vehicle from Prestige this morning after two days in the shop. A complete V25 reprogram was done and the cold idle bucking appears gone.
I will see if the 1000-1200 rpm resonance noise has been eliminated as well.
They also replaced ground straps under a BMW recall notification. I surmise the straps are akin to the old exhaust system donuts. That may have accounted for the resonant noise.

Ciao for now

 

The straps issue:

" SI B12 10 07
Engine Electrical Systems July 2007
Technical Service

PERFORM THE PROCEDURE OUTLINED IN THIS SERVICE INFORMATION ON ALL AFFECTED VEHICLES THE NEXT TIME THEY ARE IN THE SHOP FOR MAINTENANCE OR REPAIRS.


SUBJECT
Service Action: N62TU - Retrofit Engine Compartment Ground Cables


MODEL
E60, E63, E64, E70 with N62TU produced 03/05-06/07

SITUATION
When driving in certain environmental conditions (ambient temperature below freezing and low air humidity), an electrostatic discharge in the engine compartment may cause electromagnetic interference with the engine wiring harness. Consequently, intermittent engine speed fluctuation and momentarily loss of power may be experienced.

To prevent such a condition, two additional ground cables between the fuel injection rails and ignition coils grounding points need to be installed on both engine banks.

AFFECTED VEHICLES
This Service Action involves 550i/550iA, 650i/650iA coupe/convertible, and X5 4.8iA vehicles with N62TU engines which were produced from 03/22/2005 up to 06/15/2007.

In order to determine if a specific vehicle is affected by this Service Action, it will be necessary to utilize the "Service Menu" of DCSnet (Dealer Communication System) or the Key Reader. Based on the response of the system, either proceed with the corrective action or take no further action."


There is no SIB on the N62TU (4.8L) rough idle but it certainly was a frequent call for reprogramming on the 4.4L (N62) engine. However, I suspect many of the same issues apply and through PROGMAN (formerly CIP) the EGS (tranny) and DME or ECU (Engine) controls are updated and controlled.
There are other SIBs related to the 4.8L engone but they are for specific faults not related to rough idle.

 

Cobradav,
Thanks for the incredibly detailed response. Now let's just trust that the vehicle will be running up to its full capability.

 

Welcome. A ? for u. You say "sport w/step" in your signature. Is that meant to say you have the Sports Auto Tranny (with paddle shifters)? Or is that sports package and regular step tranny? I am eagerly following the evaluations on the new Sport STEP Tranny and wondered, if you had it, how is it working for u? Sorry if you have already covered this but I did not see you weigh in on Rudy's very good thread so you may not have it. I find this new tranny very intriguing.

 

I have a friend with the 4.4 in his X5 and he has a constant stumble at idle they have never been able to fix. Actually just parked the car recently and picked up a Tahoe it was bothering him so much.

 

I think my issue has been solved! Have your friend check out this reprogramming thing.