Thought I'd throw this on the table. Over the wknd, I filled two tanks from the same gas station. Drove to the 4 rotor fest at mazmart. Both cars went to the same locations for dinner and back home.
car a; 11,000 miles on rebuilt engine 260 miles and fuel indicator light, filled with 13.8 gal.
car b; 74,000 miles original engine, 314 miles and fuel gauge still reading 1/4 tank.
main difference between two cars, car a has 245 45 18's car b has 225 45 18's.
Any thoughts as to why there is such a difference. Most of the travel was highway with rpm around 4500.

 

-Tire cross-section may be a factor
-The extra 60k miles of wear on engine B
-Any number of minor variances such as fuel injector condition, sensor variation,
-Most often fuel economy is impacted by variations in driving style.

I don't believe the measuring method you assigned is useful either.
-Both cars were filled at the same time and went to the same locations and yet they have different final mileages.
-Both cars fuel consumption were measured via different methods.
--One by how much fuel was required to re-fill the tank.
--The other by visual check of the interior gauge.

 

Thanks for the response. The amount of fuel is normal for the indicator light given a 15 gallon tank. What puzzled me was the actual miles driven difference between the two. One of the two cars seems to have a sensor issue or something... given the two cars traveled the same distance physically but show different results.

 

Nevermind
driver of car b did not reset trip odometer at fill up