Not to sound dumb but how do you go about figuring milage out? My rig is a stock n/a e4od automatic 2wd 1993.5 f250 stock rims/tires and when both tanks are fuel I can go roughly 375 miles using both tanks not letting either one hit the last white line before it meet the dreaded empty red line.
Sorry my punctuation sucks spelling sucks for a fat fingered dyslexic man
To get somewhere close to knowing what your fuel mileage is...
First, you have to be sure your odometer is correct.
Second, you have to fill the tank up the same way, every time. In other words, hold the filler in exactly the same place. Hold it all the way open. Or part way. Etc. Stop the first time it shuts off. Wait till you know the fuel is pretty much to the top of the tube. Etc. But do it the same, every time.
Now... Go fill up. Write down the mileage.
Drive.
Every time you get fuel, fill it all the way up. (Remember. Do it the same way every time.) And write down the mileage.
Figure out how many miles you drove since the last fillup. Divide that by the amount of gas it took to fill up.
After several fillups, you'll be able to determine an average. That is your fuel mileage.