Mileage on my first tank

Is it normal for the first tank to be a little low in gas mileage...?

33 seems awfully low for the prius even with the short trips around town and one interstate trip which i got like 47....

 

I just did my first tank.

8.9 gal
381 miles.

The car said 38.9 mpg, but my calculations said 42.8 mpg

Now to build a spread sheet.

 

<div class='quotetop'>QUOTE(MacDude @ Mar 9 2007, 12:57 PM) [snapback]402878[/snapback]</div>

Yea, the Average MPG calculator is a bit off on the low side every time. While the vehicle is running 100% off electricity, the MPG is computed as 99.9mpg, where it should be much higher. Theoretically it is infinite, but that's a bit too complex for this purpose, but I do think they could have used a higher number than 99.9 just to offset the difference between electric propulsion and the times you're on the pedal and getting <8 mpg.
It would be best if the car had a fuel flow indicator and used that in calculating the instantaneous mpg.

On the other side, your 8.9 gallons isn't all that accurate either due to the mysterious bladder. so any hand calculations are going to be off either way, depending on how the bladder is working each time you fill up. I've decided to ignore this in my spreadsheets and just accept it as a very large margin of error. :huh:
The prius does get better as you drive more. I'm on my fourth tank now and my last one (3rd) was over 10mpg more than my dealer tank.

<div class='quotetop'>QUOTE(mayathystle @ Jan 11 2007, 08:36 PM) [snapback]374484[/snapback]</div>

man, speaking of bladders, something is up with this thing! I've never gotten more than 9 gallons in mine (fill up as soon as I notice it's on 1 block, never seen it flash), and nowhere near 50mpg for the whole tank. I have gotten above 50 for the first half if it's on the freeway or flat land. I guess that's my problem, damn hills. Maybe their quality control is lacking in the bladder department, and no two bladders are exactly the same volume. :blink:

 

My First Fill up last week was for 9.301 gallons and I got 464 Miles which equates to 49.88 MPG.

 

I just got my Prius 2 weeks ago. We live in a hilly area (NW Arkansas) and after 2 fill-ups it is becoming obvious that if we drive "normal" we get 45mpg, if we drive "conservative" we get 46mpg. I believe its the hills killing the mileage, every time there is a good downhill to glide down, someone puts a stoplight in the middle of it!