Volvo V50 Fuel Consumption and Stalling

The symptoms you describe for your Volvo V50 – elevated fuel consumption, engine stalling during idle, the check engine light, and smoke upon acceleration – are indeed indicative of a potential malfunction within the mass air flow (MAF) sensor, otherwise known as LMM. Have you observed any decline in overall engine performance, such as diminished throttle response or a lack of power, particularly during acceleration? What diagnostic steps, if any, have you undertaken to ascertain the integrity of the MAF sensor's electrical connections and the sensor's readings?

Thanks for the quick response! Yes, I've definitely noticed a decline in performance, especially when trying to pass someone on the highway. It just doesn't have the same oomph. As for diagnostic steps, honestly, I just visually inspected the MAF sensor and the wiring. I don't have a code reader or anything like that. Is there a simple way to test the MAF sensor without special tools?

Given the symptoms you are experiencing, alongside the observed performance decline, and acknowledging the limitations of your diagnostic resources, it is highly probable that the mass air flow sensor is indeed the root cause of the issue. The prudent course of action would be to have the vehicle undergo a comprehensive diagnostic evaluation at a reputable automotive service center. Such a facility possesses the tools and expertise to accurately assess the MAF sensor's functionality and to verify the air-fuel ratio parameters, thus confirming or refuting the sensor's role in these issues.

Okay, I appreciate the advice. I took it to the workshop today, and they confirmed it was a defective MAF sensor. The total repair, including the new sensor and labor, came out to 365€. Runs like new again! Thanks for pointing me in the right direction.