I'm getting low mpg on my 08 prius :(

Other folks are mentioning that ethanol in the gas is really hurting their mileage--outsized effect compared to the relatively small percent ethanol. I wonder if the initial fill contained ethanol? When you do your fill make sure it is not an ethanol blend.

The part you described about the ICE running all the time is really not normal and would indeed hammer your mileage. The beauty of this system is that the engine is only supposed to run when load demands it, with the battery supplying the difference. For example, sitting at a light with AC on, the engine is not running. This should be a big advantage for the Prius over the Civic Hybrid.

Is the hybrid battery pack running low much of the time so that the ICE is constantly charging? I noticed a thread last night about an older battery pack going bad and being replaced under warranty. Obviously any such problem on a new vehicle is going to be under warranty.

Another thing to consider is alignment. Is it pulling to one side? If you are having to apply constant countersteer to a pull to one side then the engine will have to run a lot more and it will be unable to glide without the engine running. I noticed some threads about this with new vehicles in the past. Getting the vehicle aligned eliminated the problem as best I could tell.

It sounds to me like something is definitely wrong, but it is not obvious to me what that is.

In buying cars over the years I've learned that:
1. Initial alignment is usually only approximate--particularly toe in. (Ironically, my Prius is the only one so far that I haven't had initial alignment issues with, knock on wood.) I like to follow my new vehicle while my wife drives for awhile on a straight--that way I can see if the thrust angle is way off.
2. Dealer's often foul up tire inflation. (My Accord had 55 psig in it when I picked it up and the ride was harsh but not in a good responsive way.) I slightly readjusted the Prius pressures as the front left was originally lower than the rear left, but they were all in an acceptable range around 38 from the dealer. I'm using 42/40. The 2 psi difference front to rear is to keep the right suspension balance.
3. Don't rely on their fluid level checks. They overfilled my Prius' oil slightly. This is perhaps the most common complaint in this forum.

 

Do check the tire pressure, simple and quick to do. Many people have noted fuel efficiency gains by increasing the tire pressure from the recommended pressure to 42 psi front/40 psi rear (assuming stock tires). Visual inspection will only spot severe underinflation.

Do check oil level, simple and quick to do. There have been numerous threads, that indicate that OVERFILLING with oil can/will decrease fuel efficiency. A consensus is building to have the oil no higher than the top dot, and preferably about 1/8" below the dot. Again, history with threads here indicates that when getting your oil changed, the places don't allow all the oil to drain (time = money.....draining = time) and then the fill with the "proper" amount of oil, thus leaving a bit overfilled.

Do have your alignment checked. When the cars are shipped (boats and trucks) they get knocked around a bit. It is not uncommon for the alignment to be out of tolerances. The more severe the out of tolerance, the bigger hit on mpg. There was a recent thread on this in the maintenance section (I think that was the section).

Keep your speed down on the highway. Speeding will decrease fuel efficiency quickly. There are people on these boards who get near 60 mpg at 60 mph. Up it to 70, drops below 50 mpg.

One reason that oil prices haven't increased at the same % rate in Europe is that barrels of oil are sold in dollars (throughout the world). If the dollar decreases by 10% (vs currencies) the cost of a barrel of oil will increase by 10% (assuming all else is equal). Our prices have increased because of a weakening dollar. Other currencies (that are stronger against the dollar) don't take that hit, thus their rate of increase is shallower than ours (they are only paying for the supply/demand increase.....we are paying for supply/demand increase AND weakening dollar increase).

 

I have an 08 Package 2 (Non Touring), and I got 45 mpg combined until I hit 5000 miles a few weeks ago, and now I never get below 55 combined. Just wait!

 

Yes, currency exchange rate is a key factor. The other is that European nations have hefty fuel taxes. They were paying $4/gallon a few years ago when that was considered "unthinkable" in the U.S. While they have been encouraging effeciency and funding new projects our gasoline taxes have remained too low to maintain our road infrastructure. Even some conservatives like Krauthammer suggest that it would make sense for the U.S. to tax gasoline heavily to pay for energy projects and to drive the domestic market toward better efficiency...rather than sending the same money to regimes/regions that we really don't want to support. His argument was that rather than pay the premium to someone outside the country, it should be rolled back in.

 

i'm about to finish a 3 week vacation... the lowest mpg for me is 28mpg... a car loaded down with camping gear and a trailor hitch with two bikes....

 

Just out of curiosity. Did the change in mpg just happen to coincide with your 5000 service?

 

Nope, my 5000 service is scheduled in 2 weeks! I'm actually at 4500 right now, something close to that.

 

Interesting! I'm thinking it's just the Prius' break-in period. Time to let the rings and bearings seat themselves at a microscopic level. I've read the Prius is shipped with 0w-??, 20 or 30, I forget which, for a break-in oil. 5w-30 is recommended for oil changes. It's just that there are so many posts about the same thing. It's almost like the Prius' ECU is programmed for some kind of break-in period during which the mpg is somehow affected. Or perhaps it's the learning curve time frame for a new Prius driver. Any experienced Prius owner out their have this experience with there second Prius?

 

I have 350 miles total on my new Prius and I'm at a little over 52mpg. You're telling me it's just going to get way better after 5,000 miles for no reason?

 

:_> Extra points for style, sir.

 

It's hard to avoid and not worth worrying about. Ethanol in E10 gas reduces polluting emissions, which is a good thing, and the most it can reduce MPGs is 3%. (Of course the Prius is not designed for E85, so don't use that.)

 

In the US at least, you can have warranty service performed by any dealer you want.

The apparent fuel economy of any single tank of fuel is suspect. Drive it for a while and see what happens.

The engine should stop sometimes. If it really never stops that should be checked out by a dealer.

Highly condensed advice for new owners follows.

*Always* check the oil level yourself before driving away from every oil change.

Read the Prius Owner’s Manual. Follow the service items shown in the Prius Scheduled Maintenance Guide, not a dealer’s “service package”. If those two documents did not come with the car, buy them online or from a dealer. They will save you trouble and expense.

*You cannot know how much fuel remains available in the tank when the last pip on the fuel gauge starts to flash.* If you let it get to that point fill the tank immediately. Running out of fuel and running on the battery alone can damage it.

Do not obstruct the battery system cooling vent which is to the right of the rear seat. *Do* use the air conditioner whenever you feel too warm, because it also cools the battery system.

To maximize fuel economy:
- Avoid speeding. Fuel economy in any car falls off rapidly much above 65 MPH.
- Avoid flooring the gas pedal, but do accelerate briskly. The engine is most efficient under substantial load.
- Gliding (no arrows shown on the multi-function “Energy” display screen) is better than coasting,
- Coasting is better than braking,
- Braking is better than stopping.
- Don't use "B" in normal driving (it's there only to avoid riding the brakes on long downgrades).
- Check tire pressures at least monthly, or whenever the average outdoor temperature changes more than about 10’C/20’F.
- Consider using higher tire pressures than those recommended by Toyota. Many drivers use 42/40 PSI front/rear. Anything up to the maximum shown on the side of the tire is safe, but it will change the ride and handling characteristics.

 

I had an 04 for about 60K miles and it averaged 44 when my wife (dashes from a stop) drove it and 52 when I drove it. Liked that so got another. I now have an 08 Touring with about 50K on it, It gets about 43 in the summer and about 39 in the winter. So, there is definitely a difference between the individual cars even though they have the same systems and EPA mileage estimates. I doubt the Touring model is the culprit as others report high mileage with them. The original Bridgestone tires did not wear long so I bought Michelins. Others report better mileage with them but I didn't notice a difference.
I set the pressure a couple pounds below the maximum noted on the sidewall. However, by the time I check them again, they are usually down 10 lbs or more. I had to make a panic stop on the freeway one day and the ABS braking was exceptional, definitely better than the non-touring model. I pulled off the side and stopped because the cars behind me could not stop as fast. Otherwise handling and such is not noticeably different and the cost of the 16" tires is at least twice as much. I definitely get better mileage on the highway, up to 55. The EPA ratings don't mirror my experience. However, how often do you do a lot of city driving after the car is fully heated up?
I run Mobile One and have changed my transaxle fluid and air filter. I keep the oil level down a little from full.
Using the climate control is definitely a 3-5 mpg reduction, heat and cool. Can't explain that except that the engine runs slightly more to circulate coolant through the heater core and run the A/C compressor. Fan motors don't use much current. I'd rather be comfortable than miserly but I do turn it off when I don't need it as opposed to leaving it set at a fixed temperature that makes it alternate between heat and cool. My comfort zone is pretty wide.
I suspect the variance is related to how well balanced the cells of the HV battery are but no real proof. The fact that the engine does obtain high numbers when it is running all the time on the freeway, makes me suspect the hybrid system. BTW, the best numbers I have sustained on the freeway were over 70 mph cruise control. Driving at 55-60 reduces the mileage for me.
My 12V battery went out recently and for all I know it may have been subpar since new. It failed rather spectacularly without warning. I barely got it powered on one night by fiddling with the Start button, parking brake and door openings. In accessory mode, the diagnostic screen (see YouTube) showed the voltage drop from 12 to 9.5V in about 30 seconds. Next morning, too dead to power on. I'll see if the Optima I put in makes any difference, mpg wise. There just isn't any way to know how much the system is charging the battery without an aftermarket tool.

 

Edited duplicate post due to web site becoming non-responsive