Mini Countryman Diesel Fuel Consumption Issue

High fuel consumption and poor starting on a diesel often points to issues with the air intake system. Have you checked the throttle position sensor and the engine throttle control valve for proper function and any signs of being gummed up?

Thanks for the quick reply! I'm not super familiar with all the technical terms. Where exactly is the throttle position sensor located, and is it something I could potentially check myself, or am I better off taking it to a mechanic?

Considering the symptoms and mileage, a defective throttle body or control valve is plausible. The reported higher fuel consumption and starting difficulties are typical. Given your limited experience, professional diagnostics are recommended. Continuing to drive with a faulty throttle valve could exacerbate engine problems. Prepare for a potential throttle valve replacement.

Just wanted to give a quick update. Took the Countryman to the workshop and, as you suspected, the throttle valve was the culprit! They replaced the accelerator pedal module, and it's running like new again. Fuel consumption is back to normal, and the engine starts without any issues. The whole repair set me back about 205€, which isn't too bad. Thanks again for your help!