Mercedes A Klasse Diesel Engine Trouble

Sounds like a classic case of a failing mass air flow sensor. It's responsible for measuring the amount of air entering the engine, and that data is crucial for maintaining the correct air-fuel ratio. When it goes bad, the engine control unit (ECU) gets inaccurate information, leading to all sorts of problems, like the ones you're experiencing. Think of it like a chef trying to bake a cake without knowing how much flour to use. Have you checked the air filter recently? A dirty air filter can sometimes contribute to mass air flow sensor failure by restricting air intake and putting extra strain on the sensor.

The air filter seems okay, I replaced it not too long ago. But I'm wondering, if it's just a sensor failure, why is there smoke? Is it really possible for a faulty mass air flow sensor to cause that much of a problem?

The smoke is likely due to an incorrect air-fuel ratio. If the mass air flow sensor is reporting less air than is actually entering the engine, the ECU will inject too much fuel. This results in incomplete combustion, leading to smoke, especially during acceleration when more fuel is needed. It's like flooding an engine. Given the symptoms, it's highly probable that the mass air flow sensor is the culprit. I'd recommend getting it properly diagnosed at a workshop.

Thanks for the insight. I took it to a workshop, and they confirmed it was indeed the mass air flow meter. The total repair cost, including parts and labor, was 365€. The car is running smoothly again.