Do you always fill up at the same station or same brand? Maybe they are adulterating the fuel (higher ethanol content, etc.). You can get test kits for ethanol content. Maybe your vehicle needs a tune-up? They could also be fiddling with the dispensing measurement, saying that you put in 12 gallons, when it was really only 11. Harder to check than you might think, since some operators were adjusting things to come out correct at like 5 gallons, or whatever the local authority was using to audit things. Also, internal combustion vehicles get less efficient as they age/wear.

>I've noticed that I get much less gas than usual for the same number of bars.

I'm having a hard time parsing what this means.

>- gas smells less like gas

Is it possible for a person to smell the difference between octanes? The higher octane fuels have lower volatiles, so that might affect the smell.

I love the smell of gas. It's weird. But I am def the type of person to notice a difference in smell.