On my 2007 Prius, I've noticed the readout of the MPG seems extremely sluggish. I previously owned a 2004 Prius, and on the way to work (mostly downhill) I got about 7-10 mpg more than on the uphill drive home. Likewise, on the way to our vacation home in the mountains (uphill), I got about 10 mpg less than driving back (downhill). No surprise. On my 2007 Prius, driving exactly the same routes, the fluctuation is FAR less--only 0-2 mpg more during the downhill segment than the uphill one. By itself, this might have been just a curiousity, but last weekend, I was low on gas (down to two bars on the fuel gauge), and added about 3 gallons from a 5-gallon gas can. After doing so, the fuel gauge remained on 2 bars, and stayed there while I drove 100 miles to the gas station. Is this the way the system is supposed to work?
I can't speak to the instantaneous display issue, but I'm fairly certain that the fuel gauge doesn't reset unless you add 3+ gallons. You might just not have hit that threshold for the gauge to reset.
Ichabod's correct about the fuel level reset. The '06+ MY prius consumption screen MPG display has changed since the '04/'05 MY. It is now a cumulative/lifetime readout unless you manually touch the 'reset' button on that display. The MPG doesn't reset at the time of fill up as it does on the '04/'05. Thus the further you drive between hitting that reset the less fluctuation you'll see on that display.
<div class='quotetop'>QUOTE(Shelterdog @ Nov 5 2007, 08:49 PM) [snapback]535229[/snapback]</div> 5helterdog, Check out the discussion on: http://www.priusonline.com/viewtopic.php?t=11455