PRIUS GAS MILEAGE SUCKS

I know, it's terrible...

I averaged only 53.15 MPG calculated on this tank and way down at 51.x on the last one....


Terrible.

 

I'm quite happy with my mileage. First of all, I keep the tires pressure at the factory setting because I want a less jarring ride. At 35/33 I find it decent and in city driving I get low 40's. On the highway and get 48-51 and my speeds avg 65. Not bad.

 

I let my father drive my prius for a bit and he has anything but a lead foot. From a dead stop, he would drive up to 30 without even using the engine, as he has always accelerated very slowly. I can imagine that most older people drive this way as my grandma did as well. Perhaps the bad mpg's are resulting from a very "light-foot". Just my $0.02.

 

We drove our 2009 base from CO to AZ on 10/17/09, a total of 837.5 miles in 12.5 hours. The car was loaded with golf clubs, suitcases, some boxes of stuff and two adults. The tires were at 39 psi and the cruise control was set at 79 mph most of the time.

We averaged 45.4 mpg for the first 673.5 miles (from Lone Tree, CO to Holbrook, AZ) and 63.8 mpg for the last 164 miles (descending from 6,000 feet to 1,200 feet in elevation).

If Prius gas mileage sucks, then show me another car that can match that mileage over that time and distance.

 

My lifetime average is 47.58 after 65K miles, driving a mix of city, rural, and Interstate in Central Florida. The AC is almost always on. Over time, the mileage had been going down, in spite of hard tires, careful driving, etc. Somewhere I read that a dirty Mass Airflow sensor could affect mileage, so I pulled mine out and had a look at it. It was dirty, but not really ugly. I cleaned it anyway, and my mileage (after 1 1/2 tanks) appears to have gone up by close to 5 mpg. Not bad for 15 minutes' work. There are several threads on the forum about the MAF sensor, how to clean it, etc.

2/22/2011 Update: now 47.51 after 80K miles, significantly more highway driving in the last year.

 

1 year, 15,000 miles, 53.4 mpg on average. Its also been on the slow decline thanks to the cold winter we've been having in the northeast.

 

Honestly I cannot blame your frustration. Even though the 51/60 was down graded to 48/ 45 I have been disappointed with my mileage too living in New Jersey. When I got my 2007 with 35K miles in Pennsylvannia, I took it on its maiden voyage back to NJ and got an average of 50mpg going 70mph with a light foot (no garden state style weaving and tailgating).

City/ Highway suggests if not formally that "around town" you should get the city rating of roughly 48mpg. "Around town" in the Montclair area my wife gets about 35-36 and I get around 40. She has a lead foot and does not play the game. There is a game to play when you drive a prius. If you gun it a lot and brake suddenly economy goes down. From what I hear short trips <5 miles, 35psi tire pressure (not 40+psi) lead to less than posted 48/ 45 mpg.

I'm wondering why the prius does not have a vw TDI style combustion engine. Also wondering why I did not splurge for a TDI wagon or save and get a Mazda 3 which is more fun to drive. I have always liked the functional modern way Priuses look (perhaps I am a minority) but I got the car to save $$$ at the pump and I am not totally impressed.

 

One more comment about mileage: don't necessarily trust the onboard computer estimate of mileage. My 2007 claimed I was imminently going to run out of gas but at the pump I could barely squeeze more than 8 gallons in. The tank holds close to 12 gallons. I believe the Prius computer calculates mileage based on how much gas is left in the tank and a few times my own calculation based on how much I could stuff into it varied considerably from the computer.

 

thread resurrection

Wow, talk about thread resurrection.

Please read http://priuschat.com/forums/other-c...uth-about-epa-city-highway-mpg-estimates.html to better understand what the EPA tests entail vs. what you believe the labels suggest...

As for "I am not totally impressed", what would you get instead? See how the 2nd gen Prius did at http://web.archive.org/web/20080618...-advice/most-fuelefficient-cars-206/index.htm.

See more results (has 3rd gen Prius in there) at: Most fuel-efficient cars
Best & worst cars review, fuel-efficient vehicles
Best & worst cars review, best city/highway mpg

It's a known quirk that the manual calculations can deviate significantly from MFD displayed results but if you average them both over time, you'll find them very close. My averages are within ~1 mpg.

 

i, also, am wondering why you didn't splurge for a tdi. westex, have you checked your tire pressure? they look a little low.

 

thread resurrection

Have you noticed the 1st post was from 2007 and westex got rid of his Prius in 2008 per http://priuschat.com/forums/gen-ii-prius-main-forum/42841-prius-gone.html.

 

You have a Gen 2 that has a "guess gauge". The bladder in the tank (added to reduce emissions) causes inconsistency in fills. Some people have suggested that slow filling it allows time for the bladder to adjust so you can get the full amount of gas in.

 

i did, but i still think they look a little low.

 

Re: thread resurrection

You are right, I don't know what I would get instead. I cannot argue with 50mpg on the highway....that's great, very impressive, but my wife does not drive exclusively on the highway. I don't drive much at all because I take a train into work.

There is something slightly misleading about the "48mpg" part of 48/45 reported by the EPA. This is the seventh car I have owned in my life time and every one delivered pretty much accurate fuel economy ratings for city. If it said 22/28 it got 22 "around town."

I cannot seem to get more than 40 around town when it claims 48- I think that is quite a gap. Nothing to fret about because it is better than my former Subaru, Plymouth, Mazda, BMW, Pontiac and Toyota.

I suppose this will balance out a bit. What sold me on the Prius was the 48 part of the fuel economy because this is how most people, including my family, drive.

 

I get an average of 55 MPG. There are always going to be some people that get more than what's typical and some people that are going to get less. You should try teaching your wife how to drive it economically.

 

Re: thread resurrection

It is a gap, indeed, but practice can likely fix it.

You don't have to religiously pulse and glide to get good results, but higher mileage necessitates a comfort switching to an engine-off glide at every useful opportunity. It's just the ratio of engine on to engine off time. It's really very mathematical, not mysterious - the lower you keep that ratio, the higher the mpg.

Very short trips will lower it, though, and there's nothing you can do about that except run errands at the end of longer drives. Or take your bike or walk

 

It's all about air temp, tire pressure, route driven, and driving style. During summer I average about 65mpg for just city/country driving. And I don't drive like a grandma. If anytging, the EPA measurements are on the conservative side.


PC36100 ?

 

Re: thread resurrection

I'm going to guess your city trips are short duration and do not give the Prius time to warm up to proper operating temperature or your route is fill with a lot of stop and go situations and no ability to glide along. In the City of Davis and Sacramento, where I do most of my city driving, I find it very easy to achieve EPA city ratings without trying and I can achieve much higher results with a bit of work.

I think you are still achieving great results overall, especially compared to other vehicles on the market. The TDI and similar sized compact cars will get even worse mileage in the city with short trips AND they WILL pollute more. But you already know this. I'm just happy you're taking the train when possible and driving a vehicle that is efficient and pollutes less than others. Thanks for your contribution to a better society.

 

The other major effect on reducing mileage is cold temperatures. When did you buy your Prius? With my short commute, I get low 40's in the winter, low 50's in the summer. Use of the heater will make quite a difference by itself, with use of a heater, the car doesn't get to optimum running temps until maybe 8 miles, so even a 15 mile commute will spend half the time in non-optimum conditions.

A diesel would get better mileage, but that would be more expensive, produce more emissions and have cold weather difficulty, and all that would reduce its appeal in the U.S. The Prius instead has an Atkinson-style gasoline engine, that produces power more efficiently, but not with as much torque as the standard otto (or diesel) engine. So the lack of torque is compensated with the electric motor (put another way, the electric motor allows a more efficient engine style to be used) which has its max torque at 0 RPM. You don't want to oversize the electric motor for cost and weight issues (batteries are heavy), so they came to what they thought would be the best combination of fuel efficiency and acceptable performance. You want pep and speed, you'll pay for that at the pump.

 

Re: thread resurrection

You can blame the discrepancy on the test (see my earlier link so that you can see what goes into it) and optimizations made by auto makers to do well/better on the test vs. how you drive. Even the EPA says Your Mileage Will Still Vary.

FWIW, CR, even w/the revised EPA tests still finds significant discrepancies, mainly between city cycles between their testing vs. the EPAs. See New EPA mileage figures and New EPA mileage figures, Fuel economy results.

If you want mileage help, please answer the questions at http://priuschat.com/forums/gen-ii-...-answer-these-questions-esp-if-youre-new.html.

For some mileage improvement, if driving in the city, better heater use (see http://priuschat.com/forums/gen-iii...-car-in-history-in-winter-13.html#post1249210) would help the ICE from running unnecessarily to provide cabin heat.

Other things that come to mind:
- trip length or altering the route to be more ideal
- better driving techniques
- oil level
- tire pressure
- lower rolling resistance tires
- alignment
- grille blocking in cold weather
- engine block heater