I use my Pathfinder for towing our travel trailer, almost always at 60 mph. Using CC, the instantaneous mpg readout on the scanguage bounces around between 12 and 17, with the overall average maybe 14 or 15.
A couple times I increased the speed to 63 and now the SG bounces between 14 and 20 and seems to center around 17. At 62 and 64, the mpg seems to fall off again. It appears to be repeatable but I haven't tried it long term yet. Does it make sense that increasing the speed to a certain point could increase the efficiency like that?