Qashqai poor fuel economy stalling

Sounds like the MAF (Mass Air Flow) sensor is definitely a prime suspect. The symptoms you're describing are pretty classic. When the MAF sensor goes bad, the engine's computer doesn't get accurate information about how much air is entering the engine. This messes with the air-fuel ratio, leading to poor fuel economy, stalling, and even black smoke from incomplete combustion. Have you checked your air filter recently? A clogged filter can sometimes mimic MAF sensor problems. Also, is the check engine light on constantly, or does it come and go?

The air filter's pretty new, changed it like 5000km ago. The check engine light is pretty consistent, it's on nearly all the time. If the MAF is faulty, is it something I could try to fix myself, or is it more of a workshop job? Are we talking about a simple swap-out, or does it need special tools and programming, like matching the new sensor with the air intake?

Given that the air filter is recent and the check engine light is constant, I'd bet money on the MAF. It can be a DIY job, but sometimes the new sensor needs to be calibrated to your specific engine. If you're not comfortable with a multimeter and some basic engine diagnostics, honestly, taking it to a workshop might save you a headache in the long run. They can properly diagnose it, replace it, and make sure everything is running smoothly. You could end up chasing a ghost if you're not 100% certain.

Thanks for the input! It confirmed my suspicions. I bit the bullet and took it to a workshop. Turns out, the MAF sensor was indeed toast! The total cost, including parts and labor, was 365€. The Qashqai is running smoothly again now, no more smoke or stalling. Fuel consumption seems to be back to normal too, so fingers crossed it stays that way.