MPG keeps going down with every fill up

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

 

I'm new to the v but from what I have read here and in the manual, you shouldn't try to use eco mode all the time. Its counterintuitive but that won't get the best results. As for why it would be decreasing with time, perhaps someone else has a suggestion.

 

how many tanks have you gone through?

 

I use Eco Mode almost exclusively. I think those who get better results without it are generally not used to driving a Prius and don't know the many tricks available for better mpg. Eco Mode helps make those tricks easier.

My guess is the OP has short trips and lots of A/C use which always kills mpg. The survey Andrew posted will help sort it out.

 

One thought is to reset the trip meter in the morning and see what your MPG for that day is, versus the overall average.

I didn't realize that there are 3 mpg displays: overall average, Trip A, and Trip B. If you find out that your Trip A MPG is really low, that's what's dragging down the overall average MPG. If your Trip A MPG is high, then... uh... I do not know.

Conversely, with about 500 miles on my V, my average MPG keeps going up and now sits at 48.6 (mostly with the air on, but doing non-highway driving). Yesterday's Trip A average was almost 51, which is what's obviously bringing the overall up.

 

Yes the avg mpg on the trip calculator lies. My mpg is approximately 3.o mpg lower than what the dash reads. That is great that you drive in ECO Mode all the time (so do I) but how much of your trip do you drive in electric? You should increase your tire pressure to 41psi for all tires. And finally, it sounds like you drive with a lead foot because for you to be getting 38 mpg in your Prius on flat terrain, is just plain wrong.

 

do you have a lot of stop and go? lights and stop signs? what is the epa sticker mpg rating on the V?

 

FWIW, The most fuel-efficient cars is what CR got. Last page of http://www.consumersunion.org/Oct_CR_Fuel_Economy.pdf describes their tests vs. the old EPA ones.

I'd say don't use Eco mode all the time and maybe try slightly more aggressive acceleration to force the engine to come on, unless you're creeping along (at walking speeds).

 

You have three methods you can try.

1. Accelerate faster to get up to speed then lift off the throttle. Reapply just enough throttle to maintain speed.
2. Accelerate such that the HSI bar goes to the 3/4 point (just before entering the power section). Then once up to speed, lift off the throttle then reapply just enough throttle to maintain speed.
3. Put the car in EV Modemand accelerate without going into the power section of the HSI. At around 15-18mph deactivate EV Mode and continue to accelerate with the HSI bar in the 3/4 portion of the HSI. Once up to speed, lift of the throttle then reapply just enough throttle to maintain speed.

In order for #3 to work you must ensure you are braking properly to regenerate a little battery power or else you'll run you battery state of charge (SOC) down. This is considered an advanced technique although the pros do not recommend using the EV Mode button. If this technique works for you then you can try doing it without the button.

Here is a link that provides almost all you need to know.
HSI

And remember, you will likely always be slightly behind the v's with 16" wheels.

 

I have a 2012 Prius package three (NOT a V. I know this is the V section) and I also live on the West Side of LA and I also get pretty crappy mileage around town. I know I am still in the "learning stage". I have had my Prius for just under 3 months. Most of my trips are 5 miles or under around town with heavy stop and go traffic. To go 5 miles around here can take 15-20 minutes. I try to be super careful about fast acceleration. I feel like I am going slower then the rest of traffic at times. I take my foot off the gas and try to "glide" as much as possible. I have spent many hours on here reading and watching videos on ways to help increase my mileage. I drive in ECO and leave my A/C set on between 73-75 degrees. I seem to average mid 30 mpgs. I am jealous of the people that I see that are getting 50+ mpgs.

 

Wow... I have the Prius V three and I'm complaining that I am averaging only 40mpg.. I would take it to the dealer and have the Tech's take a look at it. Honda ended up being sued by woman who bought their Hybrid
Woman sues Honda over gas mileage, wins | 9news.com
and she didn't get the mileage as stated, which many say has prompted the changes in the "stated" fuel economy, but I drive my Prius maybe a bit too fast because it's my first hybrid and I am a slow learner. But I would be very upset if I were getting in the 30's on average with my Prius V but even more infuriated with the smaller Prius. I would demand they fix the issue or give you another Prius. It's only 3 months old. Good luck... So sorry you aren't getting what you paid for

 

city driving in those circumstances can kill your mileage. hopefully with some of the suggestions above and more from people with similar type driving, you will be able to get up around 40. all the best!

 

Please answer the questions at Fuel economy complaints/queries? Please copy, paste & answer these questions, esp. if you're new | PriusChat in a separate thread if you want mileage help. Your short drives in stop and go don't help.

 

The best way to get better mileage is to learn how to pulse and glide. (Sometimes referred to as P&G on the forum) Basically you step on the gas to get your momentum going lift your foot off the gas, and then gently barely touch the gas pedal to cause the vesicle to coast, and not apply the regenerative system. I do this all the time now, it took a bit of getting use to, I even do it at highway speeds. I can get awesome gas mileage even though I drive 70+ mph on my 2 hour commute to work.

 

here is a link to a video that will help with mileage, it's for a 2010 prius, but has some great general information that applies to the prius family of cars...