What is up with the on-board mileage computer. The computer says 20.3, but my manual calculation I am getting 17.6 mpg. The rig is stock and I drive like an old man using 93 octane.

Taking it to the dealer for routine maintenance, should I have them look at this discrepancy? Has any one had a similar experience with their actual mileage and what the on board computer says the mileage is?

Wonder how accurate the rest of the computer readings are...miles left on tank and speed. I have noticed the speed off as well noticeably.

 

I know that cpu is wrong period I don't even bother to use it. The only feature I use on that part is the outside temp and I think that's pretty inaccurate at best.

Don't bother asking the stealer why it's wrong because they'll just say some BS to ya to brush it off. Those thing are never accurate anyway.

 

Mine's wrong all the time too, though it reads 17ish and I'm getting 15ish. I was reading through the service manual to see if there was any sort of calibration that can be done, but apparently not. After looking at the manual though, I'm surprised that it's as accurate as it is... the "input" for fuel consumption simply comes from the fuel gage... hardly an accurate measure of consumption. It probably becomes more accurate if you never fill the tank all of the way (where it's pegged on "F" for a while).

 

I have also noticed the the discrepancy between the display readings and actual calculations. I always reset the display every time I fill up. I wonder if the readings get closer to 'real' life if you let them continue to run on with each tank? Might have to try that experiment for a month or so.

 

I never reset my computer and it seems to be pretty accurate, it does read optomistic but not too bad.

 

I've heard that about the new 4Runners. I think they're using the European MPG standard, instead of US/Imperial.