My 2010 Prius III is getting only about 37 MPG, any reasons?

Try doing the actual math, number of miles driven divided by gallons put into the tank. It could be you have more gas in the tank than you think.

 

Step one: miles on tank divided by gallons measured at fuel pump during fill = mpg

Step two: if still unhappy with mpg, complete cwerdna's sticky questionaire in the gen3 forum and post answers here. If you are driving 80+, then 37 could be quite reasonable. You should be near 60 mpg in good conditions at 60 mph highway. Speed kills mpg. This questionaire goes into tire pressure and many other issues that could point to a problem if one exists.

step three: study here and and cleanmpg to learn how to drive for better fuel economy.

 

Your method is not accurate. Track the actual mileage and fuel, or use the mileage meter and subtract a fudge factor of about 4%.

Given winter weather and your drive, I would expect to see somewhere in the low 40s, unless you drive fast.

Tom

 

im seeing around 38 last two tanks and blame it on the cold weather and short trips.i know cold effects gas mpg to be lower but i was expecting it to be in the low 40s.i have had hybrids since 05 and can live with it.sure beats 12 mph on cars and trucks i owned prior to 05.a couple weeks ago had my oil changed at the dealership at 10,000 mi.and checked dip stick for overfill and it was fine.i always fill when its about half full.i also believe the gas here in KY.sucks.
12/10 just put 138 miles on going around 70 mph.and got 50.5 from Lexington to London Ky.up and down a lot of hills .short trips got 38.short trips are killers.

 

If it makes you feel any better, my Prius has been averaging 36 mpg in town now that it is cold. I just added the foam tube radiator blocker technique (in a different posting here) yesterday so that it doesn't work so hard to keep the occupants warm!

 

• Colder air is denser which increases high-speed drag. I can't get over 50 MPG with our NHW11 on the highway when the air temperature is under 40 F on the highway. The radiator blocks also reduce aerodynamic drag.
• Snow and ice on roadways increases rolling drag.
• Colder tires can suffer more rolling losses.
• Lubricants are stiffer including transaxle, increasing drag.
• Heaters tend to cool the ICE forcing the engine to run more to keep up with loss of heat.
• Front window, cabin defroster, runs the air conditioner to take out the water vapor in the air (look for the AC light to be green.) Try to minimize defroster operation once the cabin gets warm enough.

Bob Wilson

 

Our mileage is down a good five mpg in this cold weather.

 

What mileage is your trip computer showing?

 

I got 39 mpg on this last tank, and that is with cold temps, snow and/or ice, studded tires, and mostly short trips. Before that I was getting 45.

 

Yep..noticed the same thing here in central Illinois....was getting between 47-50 in town, now down to about 40-in town with the wife's short trips in town. I did note that as I continued to drive the car saturday running a ton of errands, the mileage started to improve as the car warmed up to operating temperatures. On a side note, a recent 2700-mile trip to florida and back, I had a net average of 49-mpg..only spent $160.00 on fuel...gotta love it!!!

 

Perhaps... but there is probably a few things you can do to improve things. Fill out the questionnaire is you haven't.

 

Cold here in Syracuse, New York with lots of snow so mileage is down here too. Was getting 55 to 58 in summer, now struggle to keep it in the low 40's. I'm told that's just the way it is in winter.