Low MPG?

[i12drivemyMP5]

I get at least 30 MPG highway with the kl v6 with a LSD 28 city/highway IIRC I get around 400 miles before my gas light comes on with 3-4 gallons left, closer to 4 and our tanks are 16.5?? So 12.5 gallons for 400 miles is 32 mpg and low end 400 miles with 14 gallons is 28.5 mpg plus my timing is a little off and my car runs rich

That's without a/c

14.5

Twice I have rolled into station dry or almost dry.
From dry to top of fill tube has shown 15.8 gal.

See bolded above...........
What was asked and answered was about the tank. Sure, the filler tube holds a gallon more. Any more correction you feel is necessary? Does Mazda need to change what the manual says too?

 

[Stickman]

See bolded above...........
What was asked and answered was about the tank. Sure, the filler tube holds a gallon more. Any more correction you feel is necessary? Does Mazda need to change what the manual says too?

True, the tank itself w/out the fill tube is 14.5 gal by the book. The issue seemed to be the variation in calculations of mpg. The differencs in shut-off points of different pumps lends the manual's value somewhat useless for calculations.
My point was, the way I get around it is to fill to top of tube, each time I'm trying to get a reading.
15.8 was just added data.

14.5. You're right. I suppose if I put extra containers in the hatch area, we could say the "car" holds even more. LOL!

 

[i12drivemyMP5]

Yes, I fill to close to brim as possible without spill each time to stay as accurate as possible for mpg calculations because as you have stated, different pumps will cut off at different times depending on their sensitivity, design & output strength. Only fly in the ointment that could still skew calculations a bit may be how well the pump is calibrated so when it is saying you you pumped 13.2 gallons, that is really what it was. Knowing that the tank + filler = approx 15.5 & filling close to brim will also enable you to know if the pump is way off on it's calibration. There is no way the pump should ever say it pumped 17 gallons to fill up in these cars without a big puddle being on the ground and your shoes.

 

[Teeson]

Why, when all I'm using to run my mileage numbers is the gas pumps, the odometer, and my phone app? I always fill the tank just to the auto shutoff, and use that number of gallons to fill up with the number of miles on the trip odometer. I wouldn't have thought that anything else would make a difference. Unless you're saying that would actually improve my economy??

Oh I'm under the impression that you changed something.. I find it helps if the weather changes dramatically or I mod the car, but no need to do it everytime you fill up.