No, it’s the smell at the pump. Nothing to do with how the engine feeds itself. Yeah, leaded gasoline smelled different. “Sweeter” or something. Maybe it wasn’t the lead, and maybe whatever replaced the lead inside modern gasoline is what smells different, but it definitely isn’t the same.

It’s not like gasoline smelled better, it’s just that I remember smelling that smell when the entire family went on summer holidays and we kids were allowed to stretch our legs while our dad gassed up the car. Good times and good memories!