Stored fuel and bad gas mileage?

[Chuck1986]

How long does it take for stored fuel to decay to the point that it gives you worse gas mileage?

Reason I ask is cuz I remember when I came home from college in December, the gas (full tank) in my Eclipse had been in there for four months. When I drove it I was getting about 21 miles per gallon! I could get 25-26 mpg in non-winter months. How much of this drastic decline in gas mileage is due to the stored fuel and how much do you think is attriubtable to the winter? (Obviously gas mileage gets worse when it is cold out.)

 

[ConfederateTyrant]

Depending on the storage conditions, most gas is claimed to degrade after about 2 months/60 days. The degradation would prevent the fuel from combusting at full efficiency, and therefore downing the fuel economy. I do not believe that winter fuel blends would decrease mileage by 4-5 mpg, however it could bring it down by 1-2 (that seems to be normal from all the forums I have read) and then the degradation would cause the rest of that loss.

 

[Alcibiades]

I always get significantly worse mileage in the winter. I have no idea if it's the blend from the refineries or the weather forcing the car to take so much longer to warm up, but I suspect it is both and mostly the latter. I normally average about 32 mpg in winter, and lately I've been getting near 38, almost all in town with much stop'n'go and idling.

How cold does it get in Tempe, anyway? Just curious.

 

[Chuck1986]

quote:

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Originally posted by Alcibiades:
I always get significantly worse mileage in the winter. I have no idea if it's the blend from the refineries or the weather forcing the car to take so much longer to warm up, but I suspect it is both and mostly the latter. I normally average about 32 mpg in winter, and lately I've been getting near 38, almost all in town with much stop'n'go and idling.

How cold does it get in Tempe, anyway? Just curious.

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Glad I'm not the only one who gets terrible gas mileage in the winter!

In Tempe it stays pretty warm around here...I've never complained about the cold, except for when the AC is on too high

But now my car is stored/driven in Massachusetts...COMPLETELY DIFFERENT STORY!