34 MPG?

A bit more info. The 34.18 mpg was calculated the old fashioned way, x miles from the odometer divided by y gallons it took to fill it. Also while I was getting this mileage my fuel consumption screen was saying I was averaging about 45 mpg.

Don't ever draw conclusions about your Prius mileage based on any one fill up. Because of the bladder-type gas tank, you never know just how close to full it's actually getting, and you need to calculate the average over several tankfuls to really know how you're doing.

My worst tank ever was 44 mpg. Where I live, MN, the cold weather and short trips do consume extra fuel but you have me beat by 10 mpg! I have a self imposed 55 mph speed limit. Is this the difference? At 75 my Prius gulps gas.

Ahem, your '05 ?

I got my '03 in October and have put nearly 4,000 miles on it. But it had 49,300 on it when I picked it up.

Yes, you might check out:

Short trips in cold weather is rough on mileage. One suggestion is to keep the initial speed low for the first mile to let the engine and drive train reach an efficient operating temperature. Another approach used has been an engine block heater. Finally, the circuits indicate there are electric heater blocks that can provide 'instant heat'. The problem is this comfort takes fuel and cuts into MPG.

New car? It should not be a problem to bring it in. Shouldn't you have a

3,000 mile oil change coming up soon?

My experience:

Good luck!

Bob Wilson

There's nothing wrong with your car. Your true MPG was 45. You can't trust calculating MPGs by hand because the flexible fuel bladder means that [gallons put in at last fill] do not necessarily equal [gallons burned since the previous fill]. On this last fill you put in, say, 10 gallons, but between fillups you actually burned 7.5 or so.

OscartheGrouch wrote:

New '95? The Prius was only a concept vehicle in 1995. I'll assume a typo and that you meant '05.

Short trips will lower MPG in any car. (short "in town" trips are not what the EPA considers "city" driving!) Winter temperatures/weather will also lower MPG in any car. (EPA only measures fuel economy in a lab at 68-86^F, with no heater/AC use.)

1 tankfull isn't enough to gage the car's performance - too many variables (was the tank full when you got it? did you fill it properly this time (different pump auto-shutoffs)? is the size of the tank the same as the last time it was filled (the North American Prius has a bladder fuel tank, which is stiffer in colder weather (doesn't hold as much))?)

Tips for better Prius Gas mileage (near end of Spring 2004 newsletter):

Prius Fuel Economy: Explaining the EPA Ratings Toyota explains what the EPA ratings actually mean, and lists ways toimprove your MPG 79 Prius Fuel Economy Factsheet: Can I expect to get over 50MPG in the new Prius? (see question #6): More MPG tips are in the Prius User's Guide: Gas Mileage Tips from the EPA: are also more MPG tips in your Owner's Manual. There is a Prius MPG calculator for the Classic Prius in the toyota-prius yahoogroup's FAQs, but I don't think anyone has recalibrated it for the 2004-? Prius yet, but it should give you some ideas where you might be losing your fuel economy: In case you can't tell from the above, things like how long (or short!) your trips are, speed, tire pressures, your driving style, terrain, outside temperatures, cabin climate settings, gasoline type used, oil type and fill level, will all contribute to your final fuel economy figures.

You haven't used your Prius a lot.... I received my 2005 in September and am just heading out to buy tankfull #18 at about 6,600 miles. I have tracked all purchases since the beginning and have also tracked the indicated mpg starting with fill-up #4. My overall calculated average is 45.95 MPG. Although most of my trips are >20 miles (a plus), my recent mileage is degraded by a lot of high speed highway driving and by cold weather.

Over the last 12 tankfulls, the average of indicated mileage at the end of each tank is now 46.1 mpg, while the calculated mileage using pump gallons is

44.6 mpg. I find the difference between tank-to-tank calculations and indicated mpg to be as much as 5 mpg. I have not been able to be consistent in determining the same "full" level when gassing up, but I haven't tried real hard. My conclusion is the indicated MPG is probably reasonably trustworthy if I recognize it is 1.5 MPG on the optimistic side of truthfulness.

Al

Thanks all for the comments. I'll check mileage over time. In the meantime check this out. I reasoned that filling at empty with a tank that changes capacity will yield results that don't mean much. But how about if I fill up at say half empty or so? The tank capacity should not matter then as I am not making the assumption that capacity is the same as the last time I filled. In fact I won't even guess how many gallons I've used, I'll let the pump tell me that. I'll just fill it to as close to full as I did last time.

Using this method today I took 5.4 gallons after I had gone 251 miles. Dividing that out gives me about 46.5 mpg. My consumption screen was reading

46.7 mpg. What I got out of this is the consumption screen can be pretty close to accurate and, more importantly, I am getting way better mileage than I thought, somewhere in the mid 40s. I feel better.

And if I heard you correctly, your Prius is new, ie engine not broken in and driving now in the winter. If that is all correct, you are doing just fine. Wait until the summer and see it really do its stuff.

greg