Interesting MPG increase from winter to spring

[gmv4k]

Driving in upstate NY during this last cold winter, even last month in early April, I was averaging 16 MPG(mixed city, highway w hills), sometime less. No lift and 265-75-16 Cooper ATP's. My coolant temperatures were running high 195-204 degrees. I needed to install a new OEM thermostat and set the jiggle valve to 6 o clock, but it was too cold to do at the time.

I was thinking how bad my gas mileage was and maybe I should get some highway tires, bc I've never been off-road.

Once the weather got warmer I replaced my thermostat and my coolant temperatures were back to normal around 192-197 (from ultra-guage). So last week I was driving my normal 100 mile route, the weather was better around 60 degrees and I saw my average MPG number try to increase. So as a test I decided to fill up at the same gas station and ZERO'ed my average MPG on the ultra-guage. To my surprise I hit 20 MPG for my normal 100 mile route. While looking at the average I decided to baby it a little, kept it around 65 mph, instead of 70 MPH and I got 21 MPG. It was almost like a game for me trying to conserve gas after awhile.

I was thinking to myself if this truck could somehow get 20 MPG I would love this thing even more.

Now maybe if I can get a new frame I would marry it

Just thought I would share.

 

[3rzrunner]

yes that is very true. also in the winter they use winter fuel with antifreeze and other additives in the gas that reduce fuel economy.
Plus each morning in the winter that you drive your car the block, the oil, gas, rad fluid is alot colder than in the spring so alot of the energy goes to warming that stuff up.
just my .02

 

[larrylegend]

I typically get about 1.5-2 mpg better in the spring, summer and fall than I do in the winter. I attribute this to the winter gas mixture. It might be worth it to look into the thermostat too though, my 99 limited has been getting slightly lower mpg's than it normally does.

 

[19963.4lsr5]

I typically get about 1.5-2 mpg better in the spring, summer and fall than I do in the winter. I attribute this to the winter gas mixture. It might be worth it to look into the thermostat too though, my 99 limited has been getting slightly lower mpg's than it normally does.

And richer air fuel ratios during warmup in the winter months.

 

[98OzarksRunner]

And general friction - cold things don't roll as easily, tires are stiffer (and air pressure drops).