There was once upon a time a car called the Chevy Sprint, 3 cylinder car, got great gas millage, 8 gal tank. BUT you could only use High Test gas or it fouled the carburetor, it was even picky about the brand used, no cutrates only name brand. Yes, I’m sure of that fact after having to have the carb cleaned twice. 4 passenger. Great little get around car, beat you to death on a long distance drive. We could go 350 miles and still have a 1/4th of a tank left.
I owned a Daihatsu Charade for 130,000 miles. It was also three cyclinder and got about 40 mpg on the freeway. I liked it, it was fun to drive. Sure glad I never got into an accident with it though.