Seat Leon Hybrid Engine Issues

Sounds like you've got a similar problem to what I had with my Leon. Is the engine light on? Could be the oxygen sensor playing up. Any DEF fluid issues?

Oxygen sensor, eh? Is that the same as a lambda sensor? And what about the NOx sensors? I'm really hoping it's not something expensive like the catalytic converter...

Yeah, lambda sensor and oxygen sensor are the same thing. I was worried about the catalytic converter too but thankfully it wasn't that. Honestly, I'd get it to a workshop. Exhaust leaks aren't good, and if it's the oxygen sensor, it'll mess with your fuel consumption. Better safe than sorry.

Thank you so much for confirming my fears and giving me the push to get it checked out. Turns out you were spot on! It was the oxygen sensor. 375€ later and she's running smoothly again. I really appreciate your help!