My 2007 prius is only outputing around 37mpg

Places to start would be tire pressure, a possible "dragging brake" and/or wheel alignment. I'm sure some of the more knowledgeable people here will weigh in soon with other ideas.

 

Please give us more clues by filling out this questionnaire, posting the answers to this thread. This covers the bulk of the common issues, except for brake drag from frozen calipers.

Fuel economy complaints/queries? Please copy, paste & answer these questions, esp. if you're new | PriusChat

 

welcome!
a 2007 with 28,000 miles likely has a very weak hybrid battery, which might be affecting your mpg's.

what would be optimal for a 12v? new ones are 13+ volts.

drive would be 'd'. b would be brake for long downhills. try to accelerate briskly and glide.

 

Please check oil level. Is the car burning oil internally?

 

When the Gen 1 Prius first came out, the 'net was filled with complaints of lower than expected mileage, these complaints were concentrated on higher mileage cars - those having more than 25k on them.

Interestingly enough, in many cases (according to the local Toyota dealers at the time) the cause was the tires themselves. There are standard, sub-standard, low-rolling and ultra-low-rolling resistance tires. Being the maintenance Nazi's many early adopters are, they were having tires replaced at ~6/32nds and because the OEM equivalent (ULRR) tires were CO$TLY, less expensive/low(er) quality tires were often fitted as replacements.

If the tires on your car are NOT listed as "LRR" (Low Rolling Resistance) or "ULRR" (Ultra Low Rolling Resistance), your lower than expected MPG may easily be due simply to low quality tires.

 

Only a few things jumped out at me:

This is an unusually large gap. Is this discrepancy consistent among numerous consecutive tanks? Single tank discrepancies are expected, especially with the Gen2's troublesome fuel tank bladder, but should average out of multiple consecutive tanks.

On individual trips, do the long weekend trips produce significantly better MPG than the short commutes?

Please do check the tires, reporting back to use the make, model, and tire size. Non-factory-size tires may mess up both the actual results, and the displayed figure may no longer match the real results. And non-LRR tire models will cause lower MPG, though not enough to explain the entire issue.

At one year old, any serious alignment problem ought to be showing up as uneven tire wear.

Don't overdo any attempts to keep the ICE off. This is easy to do wrong and actually hurt overall MPG. Get a baseline MPG (in current weather conditions) without trying anything special, then use this baseline to judge whether 'special operations' help or hurt.

Don't overdo this.

 

Sounds pretty normal to me.
We only got 7 gals fill-up today from flashing pip empty. In winter Gen2 does not fill up much. Summer you can get 9 gals from empty. Tires sound maybe non-optimal. Short trips are going to be lousy MPG. As per Fuzzy, you should expect better MPG on the long trips. Winter is the bad MPG season.

 

It's not you. I believe better comes from drafting traffic

 

Yes, traction is more important than MPG, especially in winter.

It generally is not worthwhile to change tires just for better MPG, the fuel savings generally won't offset the cost of throwing away otherwise good tires. While you can get good traction with LRR, wait until the current tires need replacement.

 

For winter you can get Nokian R2 tires they have very low rolling resistance and super good traction on snow. But of course they are a winter tire not all season so you do need separate tires (and rims) for summer.

 

ya, those tyres sound like gas hogs.

 

Hello,

You've already received a wealth of good help here, but just a few thoughts; because of the Gen 2 fuel top-off issues, its more accurate to keep a log of your fuel-ups, say with Fuelly. I've got an '05 and an '08 with a cumulative 435,000 miles, and it's my experience that the car's economy calculator is pretty accurate when compared long term to a fuel log, say at least ten fuel-ups from below 2 chiclets or so.

For any trip, leave a few minutes earlier if you can; you'll be surprised how much more efficiently you drive and how much less stressful the journey.

Don't over inflate your tires in the winter, or you'll hurt somebody. It's like putting glide wax on skis. I don't even like to do it when it's raining. Safety must command at all times.

Keeping the temperature control on automatic all the time is costly. Here in Minnesota, I tend to dress warmly and use only minimal heat mainly to keep the windows clear, at least for short trips around town, which are already inefficient. Out on the highway running the heat has less of an effect on economy, at least at low fan speeds. In the summer, the AC will really knock your efficiency down.

Wind affects MPG tremendously, and I try to drive rather slower into a headwind or direct crosswind, and faster with a tailwind.

Someone mentioned accelerating briskly, then coasting; while this seems counterintuitive, it's highly accurate. I'm not talking about stomping on the pedal, but make the car work a little- you'll get the hang of it. It gives the added benefit of destroying the illusion of the Prius barely able to get out of it's own way- be a good neighbor. Also, remember that while drafting certainly improves your fuel economy, again it's not neighborly nor safe. Plus because of the Tanstaafl Principle (There Ain't No Such Thing As A Free Lunch), you're negatively impacting the other guy's economy. The energy cost has to go somewhere.

While most people drive using the practice of "there are two pedals on the floor, and one or t'other must be depressed fully at any given time", the Prius does better with brisk acceleration and mild braking. A Prius tech told me that normal braking down to 10mph utilizes regen braking only and improves economy, while hard braking adds the mechanical brakes, causing wear and less efficiency. Judicious use of braking and coasting to time stop lights and traffic slow-downs so as to avoid coming to a complete stop is perhaps the single most effective way to improve economy. It takes a lot of energy to get an object moving, but rather less to keep it moving once in motion.

We have a lot of gen2 Prius's in our family and we've been known to load our cars similarly and drive in a group at the same speeds over the same route. Interestingly, my Mother's '05 with 250,000 miles on it is the champ, despite it being battered and torn, missing half the rear bumper and part of the front (even at 84 years old, she still takes it off road way back in the blueberry patch). My '08 is showing 49.0mpg for the last nineteen months, and that's with occasionally pulling a boat or a utility trailer.

You're not doing so bad at 43mpg and being a novice, and your skills will build fast. These are the most utilitarian and remarkable vehicles I've ever owned, and while I wish I could plug them in and get fifty or so on electric even in cold weather, for now they'll have to do.

Enjoy!