is it better to go with the flow on the hwy?

[MetroMPG]

my car's "sweet spot" for mpg vs speed is significantly less than 100 km/h. in fact i think it's closer to 70 km/h, though I haven't plotted it out yet. (it's on the list.)

that was one of the first things i thought when i saw my mpg climbing as i joined the flow of traffic on the freeway: "hmm, maybe my car gets better mileage at higher speeds" but i've since learned it's just not the case.

that's why i'm thinking it may be air flow generated by the traffic.

(i can get MAP readings on the SG. why do you ask?)