This is an old post but I thought I would put my 2 cents in. My 2011 35d with 34000 miles. Idrive says "engine malfunction operating at reduced power" as soon as I slow down to 50ish it goes away. On a 240 mile trip it happened about 5 or 6 times and after the last time the engine light illuminated and stayed on for the last 60 miles of the trip. When I started it the next day the light was off and it ran fine for a week around town.

I own and operate a diesel injection and light duty diesel repair shop for 28 years. I am very familiar with the fuel systems on these vehicles because they are virtutally the same Bosch injectors used in the newest Dmax pickups.

What I notice is a bit of a surge or "fish bite" feeling in the seat of the vehicle. If I had not changed it I would swear it was a restricted fuel filter.

I drove to my vacation home "240 miles" in Montana this past Friday and it never happened. I did feel the "surge" a couple of times when running in the 60 to 70 mph range but no light or message on the Idrive display. When I had the chance on the trip I drove the bag off the car. Several times I had 2 and 3 mile stretches of 220 to 230 kph (Canadian car) when I drive it hard it runs great. I only feel the surge at steady state driving.

With my background I would think if it were a fuel pump issue (supply pump) or even the common rail high pressure pump that it would be more pronounced at high speeds-high load- high fuel consumption operation.

Anyone that has had this issue solved please let me know.

Thanks