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Old 11-25-2013, 04:43 AM   #11 (permalink)
Basjoos Wannabe
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Join Date: Apr 2009
Location: Arkansas
Posts: 870

The Van - '97 Mercury Villager gs
90 day: 19.8 mpg (US)

Lyle the Kindly Viking - '99 Volvo V70
90 day: 25.82 mpg (US)
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I wonder how much of the problem is related to another problem I'm having, which is the SGII randomly shutting down and restarting. It happened to me on a recent 250 mile trip. On the way down, it showed I got 28 mpg (I was going to a lower elevation on average). When I refueled, the manually calculated MPG was about 26, which I kind of expected since I was going back up in elevation. But my fillup gallons used was off by about 2 gallons or more. I have noticed the miles used since last fillup sometimes don't match the miles on the tripometer by quite a lot, which would seem to point to the same problem. And BTW, I don't stop the engine and coast as other more diligent folks do; my old cars tend to have cranky starters.

The scanguage can be an accurate tool, but it has its faults. If it generally seems to be pretty close, I generally ignore the odd 2/10 of a gallon discrepancy. I'm curious though how accurate the nozzle is to pop at the same place everytime. I suspect factors such as weather, temperature of the fuel in the pump and in the car, and how empty the tank was can affect when the nozzle pops. Once upon a time I would refill the tank to the reading on my scanguage (once I had it zeroed in) and it was surprising how close it usually was.

RIP Maxima 1997-2012

Originally Posted by jamesqf View Post
I think you missed the point I was trying to make, which is that it's not rational to do either speed or fuel economy mods for economic reasons. You do it as a form of recreation, for the fun and for the challenge.
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