Big mileage jump (MPG)

[MikeTangas]

Since the time I bought my '73 280 SEL I have gotten about 11 MPG on average. This was mostly in town driving, with occassional hops on the interstate. Best I ever saw was 12.5 MPG, and that was while really babying the throttle for the whole tank.

Last weekend I took the family on a run across the mountain to meet, visit and have dinner with another forum member, JCE AKA John Elliott and his wife. I fueled up on the way out of town, and ran hard through the mountains, enjoying the curves and the power of the 4.5 as I accelerated up the grades and staying cool with the A/C blasting, basically said "to heck with the mileage", and enjoyed the ride. That trip, plus almost a week of in town driving, I got 15.04 MPG.

I am at a loss as to why I had such a big jump in mileage. It wasn't city driving by any means, but I ran hard and really expected to get about 10 MPG. Any ideas as to why the big boost in mileage?

To Deezel: Also interested to hear what kind of mileage Suzanne gets on each leg of the trip home.

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Mike Tangas
73 280 SEL 4.5