Welcome to the forum - 1st post.
It's tough to get comfortable with a fresh car, I always look at one with an analytical eye. 7 mpg change is a large change. Are you filling it up after each 120 mile freeway trip? If so, try a month of filling it at 300 mile intervals.
If the dealer accepts your mpg data they'll probably do a tune-up and/or give you an inspection - my guess.
I've not found gas brand to make a difference. My old '99 has done reasonably well with mpg as it ages, despite CEL being on for much of the past 50,000 miles. Really only speed, headwind, in-town driving, consistency in fill-up, or ambient temperature differences seem to affect mpg. Good luck.
It's tough to get comfortable with a fresh car, I always look at one with an analytical eye. 7 mpg change is a large change. Are you filling it up after each 120 mile freeway trip? If so, try a month of filling it at 300 mile intervals.
If the dealer accepts your mpg data they'll probably do a tune-up and/or give you an inspection - my guess.
I've not found gas brand to make a difference. My old '99 has done reasonably well with mpg as it ages, despite CEL being on for much of the past 50,000 miles. Really only speed, headwind, in-town driving, consistency in fill-up, or ambient temperature differences seem to affect mpg. Good luck.