Gas mileage spike on my Caravan.......?

[Recumpence]

Hey Guys,

I am currently driving a 2002 4 cylinder Caravan. The EPA rating for this thing is 18mpg. I have been averaging 22 to 23mpg since I began being careful with my driving. However, I recently had one fillup that averaged over 26mpg. I cannot account for this added mileage. My mileage has always been 22 to 23mpg at the very best when I am really paying attention to my driving. But, I did the math and cannot figure how it went up so high and went right back down again. I have been trying various things to increase my mileage, and I cannot seem to remember what I may have done on that tank to give such high mileage.

Oh, also, I have found that there is an acceleration sweet-spot that gives best MPG. If I accelerate too quickly I (obviously) lose MPG. However, if I creep up to speed too gradually, I lose MPG. It seems as though there is a perfect rate of speed increase that maximizes my MPG.

What are your thoughts?

Matt

[Frank Lee]

Fill error, combined with environmental changes between tanks.

[Recumpence]

That is my thought. However, I totally topped off the tank. I kept clicking the pump to make sure it was completely full.......

Anyway, there had to be something about that one tank that I did differently.

Matt

[MetroMPG]

Start a fuel log! Keep notes.

Was it exactly the same kind of driving? (Regular commute?)

Also, it's possible to get a bubble in the tank (so it's not completely full, even if you fill to the neck) if the car isn't level during the fill-up.

[Recumpence]

Ahh, bubble in the tank. Not a bad thought!

Yup, I keep a log.

It is funny, my father has been keeping a log for 35 years (maybe longer). He also has been coasting to intersections, filling up his tires a bit high, etc. I always thought it was such a waste of time.........

Hmm, funny how things change when you grow up!

Matt

[user removed]

I have rocked my wifes Murano (been sold) and managed to get 2 more gallons of gas in the tank. This is especially true of vehicles that have long filler necks that connect to flat tanks under the floor particularly those under the rear seat with caps located behind the rear wheels. In my VX I carried a piece of a 2X4 and rolled the left rear tire onto the 2X4 to raise the left rear wheel up to make sure the tank was completely filled.
Some filler necks enter the tank from the side which exacerbates the problem.

regards
Mech

[ksa8907]

If your next tank is particularly bad, you'll know it was a bubble.