That is just nuts! Granted, I am much more likely to pass than be passed, but I also don't pretend the Disco is my S4. Lots of hills and stop and go traffic around me, but even when I have done long trips with minimal hills, I can't see this engine and truck getting anywhere even close. It just seems statistically impossible.
For the sake of my sanity, throw a Garmin or something on the dash and see what your GPS confirmed speed is at a speedo reading of 60. Also, figure out the actual mileage of your trip via GPS/Mapquest and then see what your odometer shows. Could it be that with the pump clicking off you are getting different fills? I just can't honestly figure out how a 12 year old 2.5 ton truck that is as aerodynamic as a freight train with a 40 year old engine design can get anywhere near that! Heck, I would love to get that mileage... and maybe I could try granny driving it once but I still think I would be far away from that!

 

Well, I don't have a Garmin or any other kind of GPS, nor do I have a smart phone, which is somewhat odd because I am one of the most techy geeky people I know. But, I am running stock size tires at 38PSI, and Google maps calculates the mileage to within .2 miles of my odometer reading of the route I take, so I think my odometer is reading correctly.

We will find out on Saturday when I repeat the trip, if this last run was a fluke...

 

Well poop. Just got home from seeing the wife and kids in Rolla, Mo. Exact same trip as last weekend, same everything. Mileage this time (no A/C) was 18.419MPG. So it looks like the last time, when the station pump was having issues, it did not completely top off the tank. So the 20+MPG was in error.