MPG Display Is Wrong

As the thread title states my MPG display on the dash is off by about 2 MPG, is there a way of fixing this? My truck is a little over a month old and has right at 2,200 miles on her, I have filled up a few times since I bought it and always clear my trip and display. I have calculated the MPG and get from 13.5-14.85 but the display will read 16ish.

 

Try not clearing it. Other than that, doubt anything you can do.

 

I have only heard two people who believe that the onboard computer calculated mileage is accurate.
One of those was a guy who took a long road trip and kept meticulous records and was able to validate that (for him) by the end of the trip, the computer showed mileage virtually the same as hand calculations.
For me, not so accurate, ever.

 

I would reset the mpg and fill up (1st fill up) the car and then keep track of millage (reset trip A for example) and keep track of gallons added over several hundred miles. You don't need to fill up every time after the first fill up if you don't want to but record the gallons added ... and for your final millage reading (trip A - keep track of roll-over if any), fill up again (relatively similar to the levels of the 1st fill up - easier said than done) and see if your calculation matches the display.
I haven't tried this with the Tundra but I get a fairly accurate readings with our other cars especially on long trips but those cars have a 15 and 17 gallon tanks. Tundra has a big tank but the longer you go (maybe couple of tanks) the more accurate reading ... or just do what I do and ignore the mpg! mine has been stuck at 12.5 mpg for a long time since I have never reset it. Tried once by holding the button down and it didn't reset, I need to read the manual. I always have the display on DTE I find it relatively accurate and useful. I typically do a mpg calculation once in a while to make sure the cars running well. You can listen to the engine and figure this out but a mpg calculation once in a while is not a bad idea.

 

My mpg gauge was pretty accurate when my truck was stock. Now with a lift and larger tires, they are not. I don't have installed a speedometer calibrator.

You may try resetting the ecu (disconnect the negative end of the battery for a bit (some people say 30 minutes). Then reconnect and drive normally for a couple of weeks (this lets the ecu learn how you drive). Then do the measurement over several tank of gas as suggested above. I am not sure if that will fix the problem, but it's worth a shot.

 

Not even close. Don't bother doing the math of avg MPG it's saying and what it displays for miles to empty, it will drive you nuts.

 

Did you change your tires from the stock 32s? That would affect the odometer.

 

It's completely stock. I filled up today and calculated 14.85 (best yet) and the dash read high 16.

 

Can you add to 2008 Tundra the MPG button the the higher limited has?

 

Are you filling up at the same pump?