Volvo S80 diesel MAF sensor issue

Sounds familiar. I had similar symptoms with my old Opel Astra, but it was the O2 sensor that was causing the problem. Have you checked your air filter? A dirty air filter can sometimes mess with the air-fuel ratio and cause the MAF sensor to give false readings. Also, how many kilometers are on the car?

Yeah, the air filter is pretty new, maybe a month old. The car has 223281 km on it. Could it still be the MAF sensor even with a new filter? What exactly was happening with your Astra?

Even with a new filter, a faulty MAF sensor is still a real possibility. On my Astra, the car was running really rough, and the fuel economy tanked. Eventually, the engine light came on, and the error code pointed to the O2 sensor. Given all the symptoms, and especially the smoke, a faulty MAF sensor might be the root cause. A workshop visit is probably in order.

Thanks for the advice! I took it to the workshop, and you were right, it was a defective MAF sensor. Cost me 365€ to get it replaced. Runs like a charm now!