I have had my Prius for almost 3 years ago. I bought it used, but was getting close to 50MPG when I first got it. It's gradually gotten worse over time, but recently it's at an all time low. I'm lucky to break 35mpg these days. For reference: it is winter in the midwest so I am driving on snow/slush a lot and with the heat cranked, but the mileage was pretty bad even before winter hit. my work commute did get shorter which i know short trips can contribute to lower mileage, and i also know I don't drive the most fuel efficiently, but I still don't get why these things would make my mileage this bad. I would like to at least be over 42… Do I need to get a tuneup or something? I'm not very car savvy if I'm being honest so I may not have been giving it the proper maintenance besides regular oil changes… Any advice?
We are having the same problem but I know we went to mostly 2-3 miles trips around town. What I do is take it out on the road for a change, 50 mph, and look the 5-minutes readings (at least in a Gen2). Looking for getting some 50+ MPG bars after the warm up. I think ours is OK but I guess I do need to check the 12v aux batt health.
So the tires are pushing against the snow/slush and the heater/defrost need has the ICE running almost all the time. The tires have lost air pressure with the cold so are having to flex more. They may also be slipping on the surfaces you describe. And you don't know the maintenance history and we don't know the miles on the car. All can affect your mileage.
It has about 110,000 miles. I haven't done any maintenance to it besides oil changes since i've had it. Beyond that, yeah idk.
Like Bisco said, it is due for some maintenance, other than oil changes. Spark plugs, PCV valve... dont assume that if you bring a car IN for an oil change that they are actually checking and changing the air filter either. I also live in the Midwest (Michigan) and it is critical that you are checking your tire pressures frequently and topping off to the forum recommendation of 42psi in the front, and 40psi in the rear tires.
Its ok, we are forgiving people It has already been relocated to the proper area by the admins. You are in good company.
Is my best bet to take it to a toyota dealership to have them do all this? Any idea the estimated cost?
A weak 12 volt battery is also a likely suspect, if it is weak the car has to keep charging it....so. If you know how, check the 12 volt battery and If you have the owners manual there is a description of how to check it.
Augh. Toyota Dealership?? How rich are you? Checking the 12v battery is something you can easily do yourself. (Fast forward to 1:30, the guy narrating realllyyy a talker and no action takes place until then)
Fuel economy complaints/queries? Please copy, paste & answer these questions, esp. if you're new For another potential issue not covered in the above thread, see also: Front brakes seized? I've have similar problems on a couple previous cars, front and rear, not my Prius. The combination of winter temperatures, snow, slush, and short commutes will significantly reduce MPG.
So I checked the 12v auxiliary battery and the reading was 11.4, and then when i played with the lights it was like a 10.8… is that low enough to need replacing yet??
Also check your oil level. if the oil is over filled, it will greatly affect your mpg. I replaced my 12V battery with a yellow top because they were on sale and I was able to get it quickly shipped through Amazon. I'd replace your battery soon with an OEM (Original Equipment Manufacturer aka Toyota) battery or Optima Yellow top. you can do the install yourself easily with some hand tools.
I have the same issue, please let us know if the battery replacement fixed the issue. My MPG dropped from mid 40's to mid 30's within a month. It's seems like the engine gas engine is always running.
I was thinking about this the other day... reasons for mpg drop... and wondering if changing out the Oxygen / O2 sensors would make an improvement? I know in regular internal combustion engines, replacing old O2 sensors can make a big improvement to MPG. Does anyone know if changing them in the Prius would make a difference? Here is a link to a mileage and O2 sensor discussion. Mileage dropping each year in '07 | PriusChat
Another link for more info about changing O2 Sensors: Oxygen sensor - collar around it?? | Page 2 | PriusChat
Anyone looking for the Toyota oxygen sensor socket tool, I've found one from tool source.com for $104.95 Oxygen Sensor Socket - Toyota | OTC - SPX | 09224-00010-01 If anyone knows a place to get one cheaper please let me know, after reading this post and I'm thinking i should change out my top O2 sensor for preventive maintenance.
