Peugeot 108 high fuel consumption and stalling

That does sound like a potential MAF sensor issue, given the symptoms. The increased fuel consumption, stalling, and check engine light are classic signs. Have you checked the air intake system for any obvious blockages or leaks? A dirty air filter can sometimes cause similar problems by affecting the airflow.

Thanks for the quick response! I haven't specifically looked for blockages or leaks in the air intake, but I did replace the air filter about 5,000 km ago. Where exactly should I be looking for these leaks? Is there a specific part of the intake system that's more prone to them?

Given you've recently changed the air filter, a blockage there is less likely, though still worth a quick check to make sure it's seated correctly. Leaks can occur in the hoses connecting the air filter housing to the throttle body, or around the MAF sensor itself. Sometimes a visual inspection can reveal cracks or loose connections. However, with those symptoms and the mileage, it might be the sensor itself that has failed. Best bet would be getting it checked at a workshop.

Thanks for the advice. I've taken it to the workshop and you were spot on. It was the mass air flow sensor and after replacing it, all the issues are gone. The total repair cost was 365€. Hopefully, this thread can help someone else with similar issues!