328i inline 6 stumbles

328i, inline 6, starts fine. drive 100 yards to stop sign, give the car gas to go, and it seems to stumble or stutter. gas has to be pressed heavily to get it to smooth out. seems to get better as the engine warms up. no code or engine light comes up. thought the engine was just cold natured, wife says it does it with her even when warm, I couldn't duplicate when warm. can dealer diagnosis with no code? anyone have similar experience with this engine?

The M54 engines which I would assume is in your car have issues at higher mileages with the idle air control valve sticking due to carbon build up. Get a can of throttle plate/body cleaner and remove the IAC valve and Throttle body and clean all the build up off of the inside of the valve. If your air boots going to the intake haven't been replaced yet they tend to rip when they are older. It shouldn't take more then 2 hours to do.