Avg Mpg Vs. Tank Avg Mpg

[waymay1305]

AVG MPG vs. Tank AVG MPG. I've noticed that I average 19.4 for average mpg but the tank average mpg is usually higher which is about 23.4. What's the difference? With my combined city and highway driving I would like to assume I'm getting 23.4 mpg. Is this a good assumption?

[spgull]

AVG MPG vs. Tank AVG MPG. I've noticed that I average 19.4 for average mpg but the tank average mpg is usually higher which is about 23.4. What's the difference? With my combined city and highway driving I would like to assume I'm getting 23.4 mpg. Is this a good assumption?

The only true way of attaining MPG is dividing the number of miles driven by the actual gallons used. That said, one fill up is not a good test. You need to include a few fillups in the test. On a trip from Boston to Ft. Myers Florida I got 31.5mpg. My average MPG indicator was right on.

[1990LS400]

If you are talking about the AVG MPG and Tank AVG MPG on your trip computer in the dash and it works the same as in my 00 LS400, I would think the two readings should stay in sync if you manually reset the AVG MPG each time you fill up your gas tank.

I've never paid any attention to the AVG MPG display -- I guess it would be interesting if you wanted to know the gas mileage for a long trip on which you fill the tank multiple times. I generally keep the trip computer on Current MPG for the amusement of watching the fuel usage fluctuate from zero to 99.9 mpg. It is kind of interesting to watch the effects of terrain on MPG when I'm bored and may keep my foot a little lighter on the gas pedal.

I've kept track of fuel mileage in log books for every tank of gas for the past 40+ years -- probably left over from when gas tax was deductible on personal income tax returns. I keep a log of all repairs and maintenance in the same log book. A log book and a file folder of receipts for all repairs and the original window sticker always seems to make a big impression on potential buyers when I sell a car.