Poor Fuel mileage - typical?

^ Yup, consolidate trips, avoid multiple (mpg killing) start ups.

 

Here is a real-world example from this evening, in 40 F weather with the HVAC on Auto at 72F.
I drove 1.4 miles to my first stop (2 red lights) and for 31 mpg. After shopping, I continued my trip home (with a warmed engine) and got over 50 mpg on the remaining 12 miles of mainly highway driving.

See, the short trips kill your mileage.

 

Cold air is dense, your car has to work harder to cut through the air. Winter blend fuel is not as efficient as summer blend fuel. Cars run rich when motor is cold until normal operating temp is reached. Car takes longer to warm up, restart more often to stay at temp. Everything else has pretty much been covered here by other members.

In winter I can get over 50mpg avg as long as I don't go over 65mph. If I drive 80mph, I get 45mpg avg.

 

On the tire sidewall there would be a maximum tire pressure number, I would not exceed that.

 

B is needed only when descending mountains, ski hills, long downhills. It reduces charging, is useful only to forestall the car being fully charged and having to fall back to friction brakes only, to the point of overheating.

In short: almost never.

3 minute drives, starting with cold engine, will be killers, tough on the engine too. Yeah if practical, walk or consolidate.

 

I use the B position to keep from riding my brakes and sometimes in heavy stop and go traffic so Not to be tapping my brakes every couple seconds. Some never use it.
I would drop my tire pressure down to the low 40's.
The Prius shines in warm weather, 60's and 70's, I always thought those temperatures were the best not using much A/C or heat. The heater will force the engine to run all the time if you have it set high, after you get warm turn it down. When setting at a light turn your heater down and the engine will shut down.

 

The heater has an auto mode. Eco mode on the heater (ECO beside the fan speed) slows the fan to be more efficient. There is also an S-Flow button. When activated it directs heat mainly to the driver or front passenger if it detects one.

EDIT my earlier post was mistaken. You do not have a Gen 4 so I think the heater ECO mode is tied to the Drive Mode setting. S-Flow may not be present either.

 

Here is an online link to the user manuals. They are easier to search than the paper ones you may have received.

2012 Toyota Prius Owners Manual and Warranty - Toyota Owners

 

NO stop with the high tire pressure please.
You need to read ALL of the responses.

On the sidewall of your tires, it says what the max. upper pressure is; probably 40.
Putting in more than that can BE A SAFETY HAZARD.

Guessing at things like that which you really don't understand can be bad for your health. REALLY.

 

I suspect extreme high pressures are hard on suspension components, start to change the car's handling, maybe making it skittish going over bumps in corners, and so on. And of course comfort is reduced. With the 15", personally I'd stick around 38 psi all around, don't bother differentiating front and rear pressures. Don't assume higher and higher pressures are improving your mpg, test it if you like. And if there is an improvement, by how much, is it even measurable.

 

No need to "suspect". All of that is true in most cases.

 

maybe do some experimenting, running a tank of gas at 40, 45 and 50 to see what happens.
there is no conclusive proof of a tire pressure and mpg relationship.

 

Just some notes. Common mpg sappers on the Prius:

1. Driving technique (tons of stuff to cover here)
2. Cold weather/wind/rain
3. Having heat on before car is up to operating temps, especially in winter (partial grill block helpful) - recommend lowest fan setting until 10 mins into drive.
4. Tire pressures
5. Not using low rolling resistance tires (Never heard of Doral brand, may not be good)
6. 12V battery nearly bad (inverter pulls power to charge it)
7. Over-filled oil

Less likely both may be worth it:
1. Air filter
2. Run fuel injector cleaner

 

See this, post #9, with data from hypermiling guru Wayne Gerdes: Tire pressure for 2014 Prius | PriusChat

Basically, there's an improvement, but it is diminishing with increasing pressures. I've ran as much as 50 psi in my Prius tires (on 51psi max sidewall tires). Handling is harsher and the traction control gets triggered easily, especially when braking. I like 44/42, seems a good compromise of comfort/handling/fuel economy.

 

One more unlikely possibility would be the HV traction battery dying so the engine needs to run more to keep it charged.

 

I want to say that nothing is wrong with your prius Suzanne, and that the uphills in that area is causing your overall MPG to be significantly lower. I drove from the inner county to grass valley on hwy 20, my MPG overall was 35 and I was really trying to max out FE on the way there. On flat roads, I get an average of 6h0-70 MPGs. This car has only 149 horsepower and engine load is 100% when going up the hills, hills are killing your FE.

 

Of course there IS.....if the pressure range is wide enough.
Apparently you read a lot of stuff that you don't really understand.