Any chance you figure out which cylinder is misfiring?? (scan tool or some thing?)
change spark plugs, and check coils, (replace whichever is not functioning)
Its a pretty easy repair. failing that, replace all the spark plugs, and coils, and she should be running without misfires! (unless ...!
good luck

__________________
2003 X5 3.0i (02/2003) sport package, Sapphire black metallic / Black Dakota Sport seats. compass mirror retrofit, trailer hitch retrofit, Prodigy P2 trailer brake controller installed, PDC retrofit, Lumbar support retrofit. heated rear seats retrofitted. Running boards retrofitted and subwoofer install in progress. 4.8is Brakes installed front and back. Bluetooth TCU installed, Rear Fog lights installed. Retrofitted reclining rear seat backs.