Sprinter engine knocking and power loss

Sounds familiar. I had a similar issue with my Sprinter. The symptoms you describe, especially the knocking and jerking, point towards something serious happening in the cylinders. Deposits in the combustion chamber can definitely cause pre-ignition, which is essentially the fuel igniting before the spark plug fires. This puts immense stress on the piston and cylinder heads. I'd also be concerned about the possibility of valve damage if it's been happening for a while. Have you checked for any other codes besides the generic engine fault? Things like misfire codes could give you a better idea of which cylinder is acting up. Also, what kind of fuel are you using?

Thanks for the quick reply. I haven't seen any specific misfire codes, just the general engine fault. As for fuel, I always use the recommended octane. What was the final diagnosis and fix for your Sprinter when you had this issue? Was it definitely combustion chamber deposits?

Yes, it turned out to be significant carbon buildup in the combustion chamber. The increased compression from the deposits was causing pre-ignition. I tried some fuel additives designed to clean the system, but they didn't make a noticeable difference. Ultimately, I had to take it to a workshop. They performed a chemical cleaning of the combustion chamber. It helped a bit, but the issue came back after a while. They recommended removing the cylinder heads to clean the combustion chamber and valves properly. I know it sounds like a lot, but if the deposits are severe, it's really the only way to be sure you've addressed the problem. I would suggest visiting a workshop as soon as possible. If you keep driving like this, it could cause major engine damage.

Appreciate the insight! I took it to a workshop, and they confirmed it was combustion chamber deposits. They performed a cleaning, and the knocking is gone. Total cost was 425€. Thanks again for sharing your experience.