Mpg DTE 288 up to 377 miles now ?

So does anyone know why my full tank DTE went up from 288 to 377 miles ? 4x4 v6 just hit 15,500 I’m thinking there is a break in period on the fuel use ? Only change has been running 93 Costco for past 3 months, but this last tank the DTE went up to 377 mile just wondering why.

 

It’s just an average of previous fuel economy recorded and really means nothing, definitely not some kind of extended break in. I wouldn’t bother spending time trying to think about it.

 

Well what I suggest flies in the face of conventional wisdom; but here goes.

The Tacoma has variable valve timing. What this means is that it can detect octane related detonation and retard/advance the spark accordingly. Higher octane fuel used consistently will cause the system to gradually advance the timing resulting in an slight, but measurable, increase in power output. This can increase mileage depending on driving habits. I personally use Costco premium gas, and while I haven't seen a mpg increase nearly as obvious as yours, the truck definitely runs smoother on premium. It seems to like the fuel.

Your new miles-to-empty numbers are pretty good; but indicates 18 to 19 mpg per tank which is within epa estimates. So I find it very believable.

With Costco, the premium gas is cheaper than I will find anywhere else in town, it is top-tier fuel, and with the Costco CitiBank CC I get an additional 4% off.