I have an E24 and did the same thing, it was the crankshaft position sensor, hope that helpsA few miles from home today doing about 70 mph the car suddenly shuddered or hiccups for a few seconds like a downshift but not as harsh. It recovered then about a quarter mile later did it again for about the same duration. No warning messages were displayed like Trans Program
I turned around immediately and drove about 5 miles home without further incident.
Anyone have an idea what might be causing this problem?