Adjust mpg settings

Help me here, I'm drawing a blank.

How do you adjust the mpg/fuel consumption setting. I've done this before in the past but it's been awhile and for the life of me I can't remember how it's done.

For example, my last tank full registered 17.5 mpg on the truck display, while when I manually calculated, it was 19.8. I recall going into a screen and making an adjustment to the to bring the truck computer closer to the actual fuel being consumed.

 

Tag for knowledge

 

Also want to know this

 

Don’t know how to do that but my last two Toyota products had that discrepancy. Haven’t killed a full tank on my new truck yet to make the comparison. There’s an app I use, “mileage keeper” (think it’s free), it tracks everything using the real math mileage to gallon method and gives a long term constant MPG as well as every tank. The calculation method was always higher, consistently, than the dash meter. Not what you would think for a manufacturer to tell you are doing worse than you actually are.

 

I'm here to learn.

 

Funny, mine is the opposite.
I think very few people here are keeping a record. Mine will report tank averages in the low 20s.

The computer is overly optimistic and what I calculate is always lower....I’m averaging 19 overall.

 

You modded in a way to effect MPG? Could have something to do with it..Computer might be assuming stock which would wack out the math formula.

 

No I didn’t mod it.
I was just saying how the computer seems off in the other direction.....I thought that was clear!

To me it seems a little like the vw scandal with the computer reporting better than reality.
And yes I know the vw scandal was about it being programmed to cheat and mask detection.

 

The one in mine is very accurate, any time I hand calculate it is within .1

 

I wish mine was.

 

I have found the 2018 Tacoma fuel indicating computer calculations to be extremely accurate so far. My lifetime fuel consumption averages slightly over 20 MPG, and I always see in excess of 400 DTE after fill up. I’ve done some simple calculations at interment points, filled up at half tank, quarter tank, etc., and the full pumped compared to gauge reading was within 2% of the computer calculations.

This thread may help answer your question OP:

https://www.tacomaworld.com/threads/how-to-reset-the-average-fuel-consumption-mpg-display.401348/

 

Mine is typically spot on when comparing actual numbers or .1 mpg less on the computer than actual.

 

I believe the MPG calculations comes from the MAF sensor with these numbers run against the miles driven. If your speedometer is out of wack due to different diameter tires then of course the reported mpgs will be incorrect. This is the way UltraGauge does the calculation so I assume the built in system works the same way. Maybe not.

As I'm thinking about this, I may be recalling how I did this when I had an UltraGauge running. I know for sure there is a method to make such corrections on that gauge.

 

Manually calculating consistently comes in between .1 to .3 less displayed. Occasionally it will be more.

 

I thought they used actual fuel flow data from the injectors etc to calculate it, I can’t imagine there being a way to adjust it yourself?