Just thought I would post this. I got amazing mpg following a semi. It was getting about 35. I reset the average and it was rapidly climbing until I had to stop for a toll. I'm on my phone so I will try to post a pic now. I took a pic with the mpg at around 30. I didn't have a chance for it to stop climbing to display the true average. I was doing about 65 mph. The speed is low because I took the pic at the toll booth. I usually get apx 20-21 mpg highway. Shake n bake.

 

You'll never see that again...

 

I think it was on myth busters they did that.
they tried at different distances to see what was best. it was found that drafting a semi DOES increase gas mileage BUT you're too close and poses a danger of rearending a semi.

 

its called "drafting", racers (car, bicycle, even runners) let the guy in front "break" the wind resistance at his expense (of energy) and take advantage of the reduced pressure behind the leader.

You'll also see ridiculously high numbers momentarily if you fly down a steep hill in neutral.

 

If you do the math you will be disappointed! that average is way off. I watch and reset mine on a regular basis. And do the math every time i refuel. Trust me you mileage is still sucking an the illusion is still there.

 

Yea, but it's good to think your getting great gas mileage.

 

It is just cool to see that. I was sure that the digits didn't even go above 19.9
You have given me hope!

 

If you reset it, it throws everything way off I feel. I haven't touched mine in months and it's finally reading somewhat accurate. With that said I drafted off my dads boat trailer when going to upstate VT last year and got 25, on the Gage and calculated.

 

I try to get behind a truck anytime I can it got me an extra 60 miles on a tank once.

 

I did that with mine on a 3 mile steep grade, but left it in gear. The fuel shut off, driving the reading way the heck up there. It amounted to going about 60 mph, for the 3 miles, on zero fuel.