gs400jon

Has anyone had any luck complaining to the dealer about the inaccuracy of the computer, average MPG readout? Mine reads high by about 2.2 MPG.

rgacpa

I personally think that the computer doesn't include idling time in it's calculation. I have no basis for this presumption other than my computer mpg is more than my actual also. Perhaps there is a calculation in the software that, if idling time is used, causes a division by zero which would throw the calc off; so it excludes idle time.
Just a thought (though probably not a very good one),
Bob

Rx900

readouts r just more or less, if you want to know the exact mpg, compute it urself.

rgacpa

EGGGZACTLY!

gs400jon

So that's like saying the turn signals don't work so one should roll down the window and do arm signals. I was just thinking, if the computer is there to calculate the mileage, it should work right. The ES 330 computer calculation is correct to a tenth of a MPG.

Triplenet

I have checked mine on long trips and it also reads about 2MPG high. I just use the readout and subtract 2MPG. My suspicious mind thinks it is calibrated to agree with the EPA mileage estimate.

I do like this truck!

('04 GX with 22,000 miles)

Bob

Rx900

yeah thats what i do. triplenet, 22k, wow, u use ur suv a lot

looknow12

I have reported this problem many times. Remember you must consider fuel flow per hour to determine MPG. Otherwise you'd never get real time values, or even averages until after one tank was complete emptied and filled.

You must first take the fuel flow gallons per hour, then hours until empty (based on total tank cap.), then total miles till empty (based on MPH), then divide total tank miles divided by total tank capacity. Computers will calculate this every few seconds for real time MPG, and then take all figures since the last reset for AVG MPG.

Here's and example
MPH: 65
GPH (Gallons per Hour): 3.5
Tank Capacity: 20 Gallons

So:
Hours till empty: 20 / 3.5 = 5.71 hrs
Miles till empty: 5.71 * 65 = 371.43 mi
MPG: 371.43 / 20 = 18.57 MPG

Remember you have to factor fuel flow GPH because the vehicle even at idle will still run out of gas even if it does not move.

My guess is the Fuel Flow Meter in the GX is faulty.

gs400jon

I like that explanation. I'll see what the dealership's service department says about the error is gas mileage calculation. Thanks looknow12.