when first started in the morning or when started after sitting for part of the day my 735i 3.4L is a bit rough. If I dont give it any gas after it kicks over it dies, but after it is started and I idle it for about ten seconds it is all fine and later starts great untill I leave it alone for awhile or untill it gets real cold with the weather here in the upper midwest. It seems like it may be getting worse. Anyone have a diagnosis?

My L7 started to have the same problem, I think the problem is related to the fuel distribution, could have something to do with a weak fuel pump, or bad pressure relief valve, my expectation is that if I don't fix it soon, it will come a day when the engine will not start at all in the morning. A pressure gauge will tell us if the pump is working correctly. Good luck.

Check the cold start injector. Its the single injector on the end of the intake manifold. If it is bad or not getting a signal the car will sputter and spit when starting cold.