Mpg Computer Accuracy

[fritz04]

Hi. For the last 10 fill-ups, I have found the fuel computer in my '04 GX to be off by 1.4 - 1.6 MPG when calculated by hand using miles driven/gallons used. I asked a friend who also has an '03 GX and he calculated similar results - the fuel computer consistantly reads 1.5 average MPG higher than actual mileage obtained.

QUESTION: Can the fuel computer be calibrated to reflect the TRUE MPG? Could yours be doing the same? Try calculating by hand and see what you come up with.

Thanks!

fritz04

[dbw]

:D Actually, you the mpg output is based on the price of fuel. It may not be very accurate, but it sure makes you feel good about your purchase

[SKperformance]

umm what is your equation you are using so other owners can compare it effectivley

[denslexusgx470]

MPG computers are never accurate (had it on several cars) so if you want the real MPG, best way, of course, calculate it!!!!!!!! think of ppl back like 10 years ago, they didn't have mpg computers, they barely had power windows 10 years ago! lol

[GS400jon]

The mileage computer on the ES330 is very accurate, at least the four or five times it has been checked against hand calculation. The computer average miles per gallon is with a tenth or two of the manually calculated number. The trip computer on the GX, consistently reads 2 MPG high.

[jeffjmr]

My GX does the same thing, 1.5 to 2.0 mpg optimistic. I would also like to hear if and when someone discovers a way to calibrate it. I can also reset the average speed while driving at a steady speed on cruise control, and the computer reads about 3mph slower. If these two calculations are related to the same input data, the problem gets more confusing as if the distance the computer thinks I'm covering versus fuel consumed is less, the mpg should be pessimistic, no?

Nitpicking, to be sure, but for $50k+ I expected more.

[GS400jon]

My dealer says that the trip computer's average miles per gallon calculator cannot be adjusted but there is a fix. The entire unit has to be replaced, so they are ordering one for me.

[denslexusgx470]

My dealer says that the trip computer's average miles per gallon calculator cannot be adjusted but there is a fix. The entire unit has to be replaced, so they are ordering one for me.

Gs400jon, keep us updated. also, if ya dnt mind, tell me also if ur dealer does a good job in fixing it (meaning that of course the new trip computer works properly, and they replaced the cover of it properly without any creaking or sqeaks coming from it). i asked that cuz i saw u live in northern cal.

[GS400jon]

OK. I have already told the dealer what my expectation is with removal and replacement of the unit, as far as not creating any problems/damage.

[GS400jon]

The new trip computer is installed. The dash, among other things, had to be removed. No squeaks, no rattles, no scratches and no finger prints. I'll have to see how the mileage computer does on the next tank of gas. Interesting though, the dealer calls the computer replacement, the "outside temperature gage fix". That hasn't been an issue on my truck but I know there have been problems with the accuracy of that display in the past.

As a side note, I had previously purchased the stainless steel exhaust tip with the "help" of my salesman. Yesterday, the service department installed it for no charge. It's not a BIG deal but still nice of the dealership. I expected to pay for that. It's the little touches that makes for a happy customer.

[GS400jon]

:cries: Well, the replacement of the trip computer didn't correct the average MPG readout. It still calculates the mileage at 2 MPG higher than the old fashioned way. The outside temperature gauge seems to be more accurate now.

[denslexusgx470]

:cries: Well, the replacement of the trip computer didn't correct the average MPG readout. It still calculates the mileage at 2 MPG higher than the old fashioned way. The outside temperature gauge seems to be more accurate now.

hmmm, so the replacement seemed to work only for the temperature gauge? maybe imma go have my temperature gauge repaired there, since i now know where it is and that you didn't have any squeaks or rattles after having yours done. :D