Seat Mii Poor Performance

I saw your post about the Seat Mii. I actually have a Seat Ibiza and experienced very similar issues last year. Increased fuel economy and engine stalling are definitely not fun. It could certainly be the mass air flow meter, as you suspect. Have you checked your air filter recently? A dirty air filter can sometimes cause similar symptoms by messing with the air-fuel ratio.

Thanks for the quick reply! I did check the air filter, and it seemed okay, not brand new, but not terribly dirty. When your Ibiza had the issue, did the check engine light also come on? And did you notice any smoke? I'm getting smoke when I accelerate, which is kinda worrying me.

Yes, the check engine light was definitely on in my Ibiza. And regarding the smoke, I did not experience that personally, but a faulty mass air flow sensor can definitely cause the engine to run rich, which could explain the smoke you're seeing. Given all your symptoms, and that you've already checked the air filter, I think it's highly probable that your mass air flow sensor is defective. At this point, I would strongly suggest taking it to a trusted workshop for a proper diagnosis and replacement.

Took your advice and went to the workshop. It WAS the mass air flow sensor. They replaced it, and the car runs like new. Total cost was 365€, which is a bummer but worth it to have my little Mii back in action. Thanks so much for your help!