this reminds me of the fuel line magnets from 20 odd years ago. These were clipped over fuel lines to align molecules and give better gas mileage. You would probably need a micron microscope to see any advantage.
Normal compressed air contains moisture and while this is undesirable in aviation and Formula 1 Race Cars it causes no noticeable difference in ordinary road going cars.
As to any measurable increase in MPG, I'd say "pie in the sky",