I use 3M Black weatherstripping adhesive for all my weatherstripping stuff. That's what I would use.
If you want something even stronger than that, Liquid Nails. I don't know of anything else that's stronger.
I have seen in newer Fords EPA ratings are actually lower than what you could actually achieve. Ford being more conservative on numbers. Perhaps Bronco is heavier than competition and a big brick going against the air not very efficient.
Another reason is turbo engines under load are way more...
For everyday driving around I don't see a reason to put premium. On average 40 cents more per gallon around here. Considering Ford designed Ecoboost engines to run on regular. Some people have the means to use premium or better yet Shell premium. Go ahead. It is better. I'm happy that Ford...