Gas mileage

As stated:

1. Low tyre pressure
2. Too much oil
3. Air temps dropped
4. Winter tyres?

Edit, this is a great site where you'll find all the answers from a very helpful bunch

 

welcome to priuschat!

 

A 12V battery of that age is living on borrowed time. And this would be the time of year it is most likely to either fail or to cause various problems (including low MPG) as it nears failure.

But don't blindly replace it without checking it first. It could just be old, but still adequately functional and not the cause of your low MPG.

 

I also add our Welcome, and here is a free test of your battery

Weird stuff happening? MPGs dropping? Test The Battery | PriusChat

 

Miss Beverly?
WELCOME to Prius Chat, Ma'am!
Take a look at the above questionnaire.
It's COLD in Baston, but you should be getting better than 30-mpg!


Good Luck!

 

i would take a good look at the 12v battery, all the best!

 

...well keep in mind there are 2 batteries, we're talking about the really small one, the 12v battery in the rear trunk area. Many of us change over to the Yellow Top Optima when the times comes, but it's a bit of a chore to change it yourself.

 

Hi Beverley! Just curious, so how's your Prius behaving of late with regards to MPG? I've noticed that my 2008 Prius has also dropped down to about 50mpg (driven more like a normal car) than back in summer when I easily achieved 66mpg.

I've been experimenting with the heating and have discovered that particularly in cold weather, the higher the heating is, the lower the MPG tends to drop. This is far more noticeable when doing shorter journeys. On long distance journeys it's not that bad.

You might want to consider blocking some of the grilles at the front of the car to help the engine retain heat so that it doesn't have to run all of the time - I'm sure you've been given this advice already by someone on this site already.

I'm achieving 50mpg in the UK presently by keeping my heating controls set to a minimum of 19c and a maximum of 22c - the higher setting is for when I have passengers. The lower setting is for when I'm alone - though I've also dropped it as low as 18c once the interior is demisted. Don't be afraid to use the A/C to demist the interior - it does a great job very quickly and is very handy. Running the A/C in winter also ensures it stays healthy.

Hope this helps.


iPad ? HD

 

Also, please feel free to set your heat at 85f or HI to warm the cabin initially, but once it warms up, decrease the thermostat to 72f. On my Prius, once I lower the cabin temp below 73f, the engine shuts off and I get better mpgs. If I leave it set to 85f or the HI setting, it kills my mpgs presumably because the engine is running non stop to keep it warm to give you heat.

FWIW, the cabin comfort doesnt change much at all when set from 85 down to 72.

 

Hi Beverly, I don't know how long you have owned the car, but did you alter your driving style recently which has coincided with the oil change and tyre rotation? Just another thought. It might be a combination of all the various points raised above and perhaps you have to do a bit of fine tuning somewhere! Good luck.

 

I'm thinking 12v battery also.