Has Fuel Changed in the last 3-4 months

Don't laugh but I swear.....in the last few months, my V8's have been sipping extra thirsty. It's like it's being used up at 33% more than it's normal rate....
I don't track mielage per tank but this is more seat of the pants observation in all 3 of the 'V8s....

Am I going crazy but has anyone noticed the same or has something with fuel ....
September is about the time the winter formula is produced. Longer engine warm up time doesn't help either. Colder temps also mean lower tire pressure. A lot of little things add up.
I don't know what you have, if they can display fuel trims on a scanner, it would be worth seeing how well the engines are running.
 
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Winter blend is likely in use . Called local fuel supplier and said winter blend to arrive mid October . Drop in temps are assisting in loss of M.P.G.s'. Wind too .🌬️ 🚗
 
Just got 36 mpg on my last tank and normally get 39 to 40. I think the winter gas is correct.

Winter here is Dec thru Feb but we have the gas way longer than that. ☹️
 
September is about the time the winter formula is produced. Longer engine warm up time doesn't help either. Colder temps also mean lower tire pressure. A lot of little things add up.
I don't know what you have, if they can display fuel trims on a scanner, it would be worth seeing how well the engines are running.
This. Colder air is also denser, requiring more fuel to maintain the same air fuel ratio, and it also increases aerodynamic drag on the vehicle. Also takes longer for transmission fluid to heat up, my trucks coolant will get to 203F pretty quickly, the oil takes longer, and the trans even longer still.

but posts # 17'n 18?
Is it a large displacement car or small (my post's Q)?
These bent8s? 3.5L and above? Or 4 cyl, 1.8 or 2.3, 4?
In summer I average about 17 in my truck with its 5.7L v8. In winter, assuming cold but dry roads, 15’ish is my average. I’ve seen mid 13mpg, but that was with a lot of 4x4 driving through snow.

My 2016 Chrysler 300 would go from 24-25mpg in the summer to 21-22 in the winter with its 3.6L V6. I’ve not owned anything with a smaller engine for a few years now so I can’t comment on any 4 cylinders.
 
I know of the summer/winter recipe change. Didnt no they created different mileage. Am I correct - the larger displacements show higher mileage variability w/this change? Asa 4 banger driver I don't C it (record mileage and gal used since a kid).
You may be right, my truck with the 5.7l looses about 2 mpg in the winter and my Fiesta with a 1.6l 4 looses 1 mpg. % wise the truck is looses 12% but the car only looses 2.5% With numbers this small its hard to see in just 1 season but I keep track of my mileage with a phone app and I have 10 years of data now. When I go back and plot the fuel numbers I get a sine wave that fairly closely corresponds with seasonal gas. And I have been retired for the last 10 years so there is very little difference in my long term driving conditions or habits. The car loss may just be longer warm up but the truck which is older definitely responds to higher energy density.
 
I suspect as traffic builds, we unconsciously tend to drive just a tad more aggressively. Instead of slowing down as we see a red light ahead as soon as possible, we keep going to make sure the cars in the next lane do not take advantage to move over and get ahead of us.

Just a wild guess, no science involved.
 
All is normal with our 2 daily drivers.
20+ mpg in the 4.0L FJ, 5w-20 & regular gas
19 mpg hwy & 16+ mpg local in the 6.2L Denali - 0w-20 & premium gas
 
Normal winter gas formula,air pressure drops,extra friction in engine,tran,drive line parts, it all adds up,
 
Normal winter gas formula,air pressure drops,extra friction in engine,tran,drive line parts, it all adds up,
Except it was October when the OP posted it and 3-4 months before October is summer so that doesn’t make sense.
 
I suspect as traffic builds, we unconsciously tend to drive just a tad more aggressively. Instead of slowing down as we see a red light ahead as soon as possible, we keep going to make sure the cars in the next lane do not take advantage to move over and get ahead of us.

Just a wild guess, no science involved.
Definitely a guess.
 
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