2011 x5 35d reduced power light

[dieselpres]

I have a 2011 35d with an occasional engine light that says reduced power. When the light come on in the display screen the engine goes into a reduced power mode. When I slow down to about 50mph the light goes off and the engine goes back to normal operation.

I am a tech and own a diesel injection repair business so I am very familiar with domestic engines and the fuel system on this car. However I have never run into a situation like this.

Last week when driving 240 miles home from my Montana vacation home this happened about 6 or 8 times. I can feel it in my seat a little bit before the light comes on. I would call it a bit of a surge or fish bite feeling but cannot see it on the tach. If it was a Duramax or Dodge I would swear it was a plugged fuel filter.

This has been happening on and off for a month. I changed the air and fuel filter soon after it started but has made no difference.

After this "reduced power" showed in the display several times the engine light came on and stayed on. The next morning when I went to work the light was off and the thing ran fine all week around town and on one 60 mile round trip on the highway.

I drove it back to my vacation home on Friday and I could feel a bit of a surge a few times but no light this time over the 240 mile trip. The thing runs fine and there was a couple of times I had it well past 120mph for some straight away stretches with no problem.

Anyone run into this?? It is under warranty and I have had it to the dealer but they cannot find anything.