Disable NAV and MPG increases?

Here is a strange one for you. About a week ago I unloaded the NAV DVD and turned off the MFD. I still get the volume control and Bluetooth prompts at the top of the screen, and hopefully other more important prompts if they occur. I don't ever use navigation, and seeing it tick away over there all the time seems like a waste. I drove back and forth to work like usual last week and noticed a significant change in vehicle-reported miles-per-gallon. I don't ever bother with a manual calculation since the number I see seems reasonable. I usually drive the same route everyday, 140 mile round trip, 5 days a week. My roundtrip average is usually in the 50-52 mpg range. By mid-week my mpg was better than 53, and by Friday it was 54.6 mpg. These higher than normal values continued into the weekend running around town. Nothing else has changed with the vehicle, no recent maintenance or tire changes. Even the weather is the same, a rather warm February thus far. I will continue to monitor and maybe do some manual calculations to confirm. I don't think there is any connection between NAV and MPG, unless I'm missing something. Thoughts?

 

So Monday and Tuesday I was driving in 40 mph headwinds and the mpg dropped back down into the 48-50 mpg range. Yeah, probably just a placebo effect of some sort. I'll keep an eye on it. Usually an mpg thread is about the numbers going in the other direction and the "how come".

 

Still monitoring the situation, and with lighter wind speeds now the mpg has increased back up into the 53-54 mpg range. I have confirmed the reading with manual calculations on the past 5 refills and it is within a couple tenths of a mpg. Everybody is waiting for the other shoe to drop when I put the NAV disk back into service. Stay tuned.