I have noticed that on my 2002 Siennaa that it gets around 24 mpg at a steady 70; 26 at a steady 65, and it has 217,000 miles so, yes, I am sure.
There is a state in Mexico where the speed limit on a high speed toll road is around 50 mph. It is actually too small to determine mpg. I have long wondered how efficient it is at a steady 50.
I lose usually one tire a year in Mexico. This year I lost two. Road hazards. So, I bought two local tires, Cooper Classics. He said he balanced them, but when I hit the highway over an hour away (local speed limits are around 38 mph) anything over 50 was clearly out of balance.
So, when I started my 840 mile trip back to the border for my annual visit, I had to keep my speed down to 50. The first fill after 169 miles which included roads so bad I averaged 25 mph for two hours, it came out to 24 mpg, which is pretty high for that hard driving.
The next one was another 387 miles and the fill-up took 43.12 liters, my calculation shows that as 11.391 galllons, = 33.974 mpg at a steady ~50 mph.
Last fill was in the US. Alas, it included around 70 minutes in traffic waiting for immigration, in gear with motor running. Still, it was 286 miles and the fill took 10.371 gallons for that leg. 27.58 mpg.
Total trip was 30.92 mpg.
I don’t know how much gas was used in the waiting on the bridge over the Rio Grande. A half gallon? A gallon? Any ideas at all?
Balancing at Pueblo tires cost $25 and it seems stable now.