2007 "poor" gas mileage

If "recently" means a few weeks, just drive it a while and see.

 

Possible culprit?

"Do not disconnect your 12V battery any time within 2 weeks or so before
the event. The car's computers learn certain values as you drive, and
use them to create best-economy running conditions. If the battery gets
disconnected, those learned parameters get erased and fall back to
internal defaults which may not be as optimized for mileage performance."

source: http://techno-fandom.org/~hobbit/cars/prius-rally-hints.txt

More:
http://priuschat.com/forums/gen-ii-...does-prius-ecu-learn-your-driving-habits.html

Recently in cold and moist weather I've had trouble getting the ICE to shut down. During this time I've experienced the same issue of lower mileage as I'm trying to hypermile, but I've found a few ways around it, maybe they'll work on your car as well. Mine's also a 2007 by the way.

First trick I do is to simulate pulse and glide by just letting regen kick in completely if it's a slight downhill. I might pulse very lightly here and there (well, with ICE on it's always pulsing I guess) very briefly to keep it moving.

Another thing I've found which I prefer is that if the terrain is relatively flat and I very gently apply the pedal to accelerate (but an extremely slow acceleration), that I can go for example, anywhere between 25 mph to 30 mph and hit 50+ mpg. Usually I do this when I've just pulsed and tried to glide (but to no avail, I see the engine's still on), so it's when I'm just reapplying the accelerator to stop regen. For the first several seconds I see the usual, gross 25 mpg, then 30, then usually it "pops" up to 40s mpg, and quickly thereafter if I keep the foot very still, 50 and above. If you can keep the pedal constant the mpg will stay right there. I find if I try to slow down to test if glide is available at all I pretty much have to repeat the process, wasting gas as it goes down to 25 mpg or so to restart the pulse.

I've been able to get about 45-60 mpg for the five minute bars with these previous two techniques even when ICE doesn't shut down.

 

I too have been experiencing much lower mileage of late. The average for the last 8 tanks is 38.1 with a low of 32.7 and a high of 43.3. Tires (Pirelli P4's) are 40/38 and recently ticked up to 42/40. Bought a new 12v battery from eLearning and had the dealer install it for $40. I checked the voltage using the procedure posted here and found that the first step showed it floating between 12.1/12.2. With the load it fluctuated between 11.8/12.0. The final check showed it about 13.9 on the new battery. I don't drive all that much (2007 with only a tad over 40K). A lot of my trips are short (under 10 miles but below 50mph with short bursts on the highway). I've never gotten anywhere near the EPA estimates with 53 being a high. Mostly in the low 40's. Don't have a heavy foot and try to pulse and glide where I can. Now the wind does blow in OK a lot...lol

 

http://priuschat.com/forums/gen-ii-...-answer-these-questions-esp-if-youre-new.html

I don't know anything about those tires, but those could be responsible for some of your mileage hit. Your short drives are killer for your mileage and also not good for charging up the 12 volt. Your numbers will be closer to CR's city numbers at
http://web.archive.org/web/20090628...-advice/most-fuelefficient-cars-206/index.htm given the last page of http://www.consumersunion.org/Oct_CR_Fuel_Economy.pdf.

I got a http://priuschat.com/forums/gen-ii-...hargers-obd2-disconnect-reconnect-cycles.html to help keep the 12 volt battery topped off when I used to only have short drives. Don't bother w/ones connected thru cigarette lighters. The ports are dead (disconnected) when the car's off.

 

Did you ever find an answer to the low city MPG on your second 07 Prius? We just purchased an 07 Prius this summer, and our city mileage is also around 34 mpg- now some of this is due to short, less than 10 minute trips- but even on longer city driving trips, we are not get much better- and we should be by all accounts. I have done some extensive reading on this, and it is not a matter of 'pulse' driving, or weather, or other techniques- it is not the oil or oil level, or the 12-volt battery, and the rear brakes do not seem to be grabbing. I suspect the hybrid battery pack may be weaker- this seems confirmed by the comparison of your two 07 prii- though as per your thought I have also wondered if the ICE is kicking when it shouldn't. I have not found much with this set of conditions. Anyway- any answers?

Oh- you can turn off the back-up beep, but I do have the steps near me right now.

 

I "don't" have the steps near me right now;-)

 

^^^
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