Cate&Rob Thanks for the knowledge down load. I had never noticed the "buzz" until I fueled with premium one day when I needed 33 gallons on a fill up. I also noted that throttle response seemed less, though I am sure that was very subjective. The fuel milage on our 2020 was about 10% below the value of running regular on that one tank, perhaps with extended use the computer would adjust and things would improve. I have heard rumors that certain Ford dealers might reflash your ECU to obtain the improved torque values of the 18 to 2020 3.5, rumor only. Again, Thanks,

Dave

I tested the 2.7L and 3.5L 10 speed trucks and could feel the firing frequencies of the 3.5L V6 but did not find it anymore objectionable than the AFM in my truck. Lol Since premium fuel would result in increased torque at the same airflow, it may be possible to feel slightly different than regular at the same load. Since I've worked with fuels only to be used for cert, they all would contain 10% ethenol and would be the standard everywhere other than Brazil that can use E100 in some applications.. We can buy Sunoco blue here which is E0 but its also leaded and will destroy the catalytic converters in modern vehicles. Otherwise in Michigan we have recreation fuel which is E0 unleaded.
Calibrations are corporate controlled and held tightly to emissions standards and to the certification that the truck was originally registered to, so they cannot legally be changed independently or upgraded to a different model year without a new cert.
Jim

Guest Yea, I wondered about those rumors on that. Evidently the clear non ethanol premium here is supposedly unleaded and works great in power equipment. My thought on the blue recreational fuel is that it may well be 100LL aviation fuel, looks and smells the same.

Dave

Thanks TXBuckeye Great feedback 👍🏻