33.4 MPG, Down over 10MPG

Well, Monroe Weather Forecast and Conditions Michigan says it's 18 F in Monroe, MI right now. Monthly Weather Forecast for Monroe, MI - weather.com has a temp history. From that, I'd say it's pretty cold.

Doing anything different w/the HVAC system like leaving the fan on w/heat above LO when the ICE is cold? Not that this will help you identify the problem (if any), but if you aren't already, perhaps you should start blocking the grille?

 

Grasping at straws, two unlikely possibilities:
* Faulty shifter mechanism resulting in driving in "B" vs. Drive
* Leaving the windshield and/or rear hatch defrosters on continuously.

 

I like your second guess Rokeby, having seen the massive hit our Prius MPG takes when my wife forgets to shut it off.

 

How do you get it to 33.4? I just bought a 2008 Prius 2 weeks ago and frankly I had never even considered buying this type of vehicle. I generally feel I should support the economy and infrastructure by paying my share of fuel costs and taxes. I've been trying by mashing the accelerator, sudden stops and starts. Usually short hops but occasional freeway runs. I can't get this thing to run out of gas! Don't know what I'm doin' wrong. Can't seem to get much less than 40 MPH. Then I made it worse, I went out and bought some Energy Saver a/s or something like that and bummer my mileage shot up to 45 MPH in the 5 degree weather we have been having lately. Can't help the economy that way and not enough road taxes to build nuthing. I simply can't match your 33.4 no matter what I do. When you find the secret please post so we can try to duplicate your success.

 

Certainly, if the test conditions or pass/fail criteria are inappropriate. Use the built-in self test. If the battery passes that then it is certainly good for Prius use.

It's also gruesomely possible to leave the car ON (running) when parked and uselessly burn some gas. Do all drivers always lock it?

Has a 300 pound guy joined your car pool?

 

wow...

 

Could ethanol cause this significant of a drop in mpg? Just a thought. Maybe your gas station has switched over to ethanol recently. My mpg has been dropping over the last 6 months too. I was averaging 44 to 47 for the first 40,000 miles on my 2008 Prius, now it has stabilized to a consistent 37-39 mpg (which is very irritating) I haven't seen 40+ mpg for a couple of months now and I was blaming it on cold weather and the fact that I can't seem to find anything except ethanol. Now I am in Southern CA (warm weather) and my mpg is still under 40.

Thinking about buying a Scangauge. it would probably pay for itself in less than a year if it could isolate my problem.

 

Cold weather takes a toll, no doubt about it. I'm used to hovering around 60 mpg most of the year, but for the first time that I can remember, my 100 mile drive to work ended up below 50 mpg this morning. 48.2 in fact. Even with grill blocking, 9 degrees F is cold

 

Dareniott,

I am having the same issue, sort of... And on top of that, the system is telling me to add fuel and the "guage" says less than a qtr of a tank, but when I fill it I am only getting about 7gals in. This issue started suddenly about a month ago.

I have a 2005 Prius with 153k some odd miles on it! I drive 100+ daily just to and from work. I love my car and it has been awesome to me. I bought it for basically the same reason as you, "to drive the way I do and still get o.k. mileage instead of getting 15MPG in a car that otherwise would be getting 24-25". I was getting 43-44MPG winter and 46-47 summer, but it was still better than my Mazada 626! I had the tune up done at 126k (Feb 09) and though the tires are now a year old. They are rotated at every scheduled oil change with no reported issues. Also, I haven't noticed any drag or pulling. I am surprised that I haven't had yet to replace my brakes yet.

Any suggestions??

 

7 gallons at a fill is not unusual. Don't try to outguess the gas gauge, because sooner or later you'll run out.

 

My 2007 Touring has 55,000 miles on it - and I also have watched the mpg drop dramatically in the last month. I used to see 49 - 51 in warm weather. When the snow and cold season hit the mpg would drop to 43, but I had switched the stock tires for Bridgestone winter tires - and expected a drop. After the winter ended I put the stock tires on and the mpg returned to 50.

I replaced the stock tires a month ago with Nokian WRG2 after reading other owners satisfaction with them here. There traction in snow has been almost as good as the Bridgestones. The first few days the mpg dropped about 3 mpg which didn't surprise me. Since then it has continued to drop and is now running 38 mpg. The tires are 42/40 on the pressure and the alignment was checked when they were installed by the dealer. I am going to check the other items I have seen members suggesting to check here. One thing I have noticed is under full acceleration there is a surging in the drive train which seems abnormal. Any ideas on what could be causing that?

 

Winter gas + cold driving + heater and defrosters + shorter trips = 10mpg.

 

Can you give a more detailed description?

 

BINGO!!!!

Buy a scan gauge, plug the grill and inflate the tires to ~42 psi.

Winter gas accounts for several, and ethanol blends account for a bunch! I find that when I drive in the midwest my fuel mileage drops like a stone. Interestingly it drops more than the 10% ethanol fuel is supposed to save in energy! What god gives with one hand, he taketh away with another. (Besides, corn is food!)

As for the Nokians WRg2. Keep them inflated to ~42 and your mileage should be just as good as with the OEM tires.

 

I'm not saying ethanol is THE problem, but is grass and algae food too? (technically yeah, but anyways...) They can make ethanol out of a ton of stuff, including different various waste products in the food/drink industries.

I can't wait for the world to go fully electric. Hydrogen might be ok, IF they can make it 100% from renewable energy, but I hate the idea of having to rely on someone else to fuel my travels. I would want to furnish my own fuel from solar or something.

 

A little energy information.

100% renewable energy is a laudable goal, but we aren't going to get there with much of todays technology. We need (as a population) dramatically drop consumption.

Hydrogen in general takes more energy to produce (through electrolysis) than it gives in hydrogen, and is therefore a loser IMHO!

Basic ethanol can take more energy to grow than it gives, corn based. Celluosic (sp?) based ethanol has a bit more promise. That said, an interesting stat, and I admit I am quoting from memory: The earth grows a total of about 20 terrawatts worth of biomass per year. That is all the plants, all the animals, all the algae, all the leaves etc.

Humans burn ~16 tw of power, so even if you could replace 100% of fossil fuel with biomass you would be forced to burn ~80% of EVERYTHING grown each year.

The basic problem is over consumption, and the fact that fossil fuel is so energy dense, a little goes a long way!

The answer, IMHO, will lie in reducing consumption in smart ways, using solar/hydro and wind to great advantage etc.

 

I'm not familiar with the stat's on total biomass (not saying it isn’t true though) but here's a surprisingly simple calculation that also illustrates the immense difficulties of completely replacing oil with biofuels.

- Average per capita food energy intake : 11.7 MJ (2800 Cal per day).

- Average US oil consumption per day : 0.067 Barrels (20.68M Barrels / 308M people).

- Energy content of crude oil per capita-day : 411MJ (0.067*6118MJ/Barrel)


So the daily energy consumption from oil alone is already about 35 times (411/11.7) that of the food consumed. It basically means that to replace oil with biofuels we'd *only* have to increase our agricultural output by about 3500%. Now a 10% or 20% increase mightn't be too hard, 50% to 100% might even be possible, but 3500% - that's got to be seriously difficult.

 

The idea is to burn less... like driving a prius, insulating your house, or moving closer to work.
Burning biomass instead of fossil will be better, and eventually essential, but even then...less!

 

The point is, we need to only use what energy we are provided by our energy source at any give time. (SUN) However, we are using stored energy from a distant past, and that is the only way we can currently sustain our population at it's current lifestyle.

 

I, too, have this problem. Over the past 6 months (before they switched to winter blended fuel) my fuel capacity and fuel mileage has gone down significantly. The tires are fully inflated, and I have gotten off the highway to give the brakes a feel, and they are cold. Has 45,000 miles on the original tires, they're almost needing to be changed. But also, recently, when I am down to 1 flashing pip on the guage, I refill, only to get no more than 7 gallons in (well short of the 11 gal capacity). There does seem to be a slight drag, but the tires/brakes all seem fine.

Any ideas?