2003 3.0 stumbles on cold start

[80stech]

On the M54 it could be that the brake booster/grommet is leaking. Spark plugs are critical with individual coils because they produce a lot less voltage than old school coils, also going to an iridium or ruthenium plug with wire electrodes can be a big improvement in igniting fuel mixture. My E70 had a stumble (sometimes stall) after starting and it turned out to be carbon build up from the previous owner not using premium fuel, a few tank fulls of premium was the answer to that.