John and also Doc,
The 13 mpg didn't hold, it's now more like 14 but we haven't been away from this general area and we are very, very flat. Our home is at the highest point in Sarasota County and that's only 27 feet. My truck is geared for the highway and has a 3.55 axle
ratio. At 70 mph we are only at around 1400 rpm. Most have a higher ratio as they are more likely to be hauling a heavier load. Our truck was never designed for hauling
freight. Ours is also just enough older that we don't have all the emissions add ons which you do and those also really cut into your mileage. None of the new trucks are as fuel efficient as the older ones. My son has two nearly Identical International 9900is
with the same engine and the older of the two gets 2 mpg better than the newer one.
It's all because of the crazy formula which the EPA devised to calculate emissions.
It's based upon the percentage of emission and not the total which was actually putting less total carbon than the new formula which they have mandated.
Les
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