Warm weather Fuel economy boost ?

I’m suddenly getting over well 10% better fuel economy in my regular suburb driving. No change to highway fuel economy.

I’m in the northeast where the weather suddenly reached the 50s/60s this week, up from 20s/30s in the previous weeks.

Is there a warm weather relation to fuel economy?

 

Yes. Fuel economy suffers in the cold. I seem to average about 1-2 MPG better in summer than winter

 

Interesting. I’ve never noticed any difference in any other car I’ve driven. But those were far lighter sedans. I guess it’s different for a 5000 pound vehicle.

 

Alot of gasoline suppliers also switch to a "summer blend" this time of year, which is typically better for mileage than a "winter blend". If you can buy non-ethanol gas, in your area, you shoud see even better fuel economy.

 

Here are some of the reasons for this. Wind resistance being a factor might explain why you're noticing more of a difference with the 4runner versus a small sedan.

 

This is true, also. Although, I haven't seen any improvement in fuel economy from non-ethanol gas in anything newer I've driven.

 

Optimum fuel combustion occurs at 72.5 degrees if Im not mistaken....

 

Ah ok so there definitely a warm weather link. I just never noticed before in small fuel efficient sedans. I’m just happy to go from the 16-17s to low 19s in suburb driving.

 

My Z28 actually pumps coolant through the intake throttle butterfly housing to warm the incoming air. I’m sure the 4runner has something similar?
But ya I lost 3 mpg in the Corolla with the cold temps...

 

Same results here, still on winter gas and as soon as it is above 50* economy goes up. A buddy's '18 Camry is showing the same characteristics.

 

I'm also in the N.E. I doubt your suddenly noticing this from one week to the next. Seems rather quick and drastic.