DMax Fuel Volume Regulator Issue

I experienced very similar symptoms a while back with my DMax: check engine light, rough idling, and a definite lack of power, especially when trying to overtake. In my case, the issue was indeed related to the fuel injection system. More specifically, the fuel volume regulator. This regulator controls the amount of fuel delivered to the engine, and when it fails, it can cause a cascade of problems like the ones you described. It's located on the high-pressure fuel pump. Did your mechanic check the fuel pressure readings? Abnormal readings can confirm a faulty regulator.

Thank you for the prompt response! My mechanic mentioned something about abnormal fuel pressure readings, but I was too stressed to fully absorb the details. Was the high-pressure fuel pump also defective in your case? What was the final diagnosis and repair process?

From what you are describing and from my experience, it does sound like a faulty high-pressure pump. Considering your mileage, it's not entirely unexpected. The pump is a critical component of the fuel injection system, and it's responsible for delivering fuel at the correct pressure to the injectors. In my case, replacing the high-pressure pump along with the fuel volume regulator was the only solution. I would recommend getting a professional diagnosis from a reputable workshop to confirm that the high-pressure pump is indeed the problem before proceeding with repairs. It is also possible that the fuel injectors are defective, so they should also be tested.

I wanted to share what happened with my DMax and thank you for your help! Following your advice, I took my DMax to a trusted workshop, and they confirmed a defective fuel volume regulator and a failing high-pressure fuel pump. The repair cost me 1510€, but the engine is now running smoothly and powerfully again. Your insights were invaluable in helping me navigate this issue and avoid potential misdiagnoses. Thank you again for your expertise and willingness to help!