Mercedes B Klasse Diesel Running Lean

The symptoms you describe do indicate a lean running condition. Before replacing injectors, consider other potential causes. A defective mass air flow sensor can provide incorrect readings, leading the engine control unit to reduce fuel delivery. A malfunctioning EGR valve could introduce excessive exhaust gas into the intake, leaning out the mixture. Have you inspected the spark plugs for signs of abnormal combustion? It's like diagnosing a heart murmur – you wouldn't immediately schedule open-heart surgery without first checking blood pressure and cholesterol levels. I experienced similar issues with a Skoda Octavia, and it turned out to be a faulty mass air flow sensor.

That's interesting, thanks. The spark plugs are new. How did you pinpoint the mass air flow sensor on your Skoda?

It was a process of elimination. The check engine light illuminated, prompting a diagnostic scan that revealed lean running codes. After verifying fuel pressure and injector functionality, the mass air flow sensor was the next logical suspect. Its readings were erratic when observed via live data. Think of it as a detective solving a case. Given the mileage on your Mercedes, and the potential impact on the catalytic converter, I'd advise a thorough diagnostic check at a reputable workshop. It's better to be safe than sorry.

I appreciate the advice. I took it to the shop, and you were right. It was the injectors. I replaced them, and the car is running perfectly now. Total cost 515€. Thanks again for your help!