[DrVette]

did either of you consider getting a cold air intake for the summer? I heard that increases FE quite a bit (in some cars)

Higher intake temperatures promote more efficient fuel burn.

Lower intake temps allow higher power levels.

These items are in "general" for stock vehicles.

 

[DrVette]

The 78mpg @ 56 mph, was this downhill ?

I know several spots where you have a 50~ mile down hill grade, like leaving Salt Lake or south from Las Vegas.

The best I've gotten for 125 miles was a DIC "indicated" 61.8 mpg on rolling terrain at 41 mph

Sounds like you got a "good one"