How would it know you had premium?
Where do you get this mis-information? They measure gas consumption by knowing how much gas flows through the fuel injectors.
Sorry…but that way of measuring gas consumption is NOT accurate. A injector fires less then an ounce of gas at a time. There’s a good portion of the gas that is NOT burned. Injectors do NOT put the EXACT same amount of gas each time. If they are off by just 1/16 of an ounce each time then the digital calculations will be off…and your engine wouldn’t know the difference. I’ve replaced clogged fuel injectors that the car ran fine on…One injector was putting less then 1/2 the amount of gas it was designed to to…the other 3 were way low too…So as I said before…The calculation done by the digital MPG meters are very very inaccurate. They may be accurate for the first 5k miles…but after that I wouldn’t trust them.
Same way cars know when someone is using 87 octane in engine that was designed to use 91 octane, only in reverse.
I have a bubbler to remove the Radon in my water…This device will also remove MTBE if it’s present. Luckily I don’t live close enough to a gas station or anything else that can contaminate the water with MTB. My water is NATURALY contaminated (Radon, Magnesium, Arsenic).