2007 Toyota Prius Red Touring Edition Side Shot
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5 Reasons Your Toyota Prius Is Getting Awful Fuel Mileage

Has your Toyota Prius lost some MPG? Well, you are not alone. Here are 5 reasons why you are getting bad fuel economy, and what you can do about it.
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So, your Toyota Prius has lost 5 miles per gallon, and now you are wondering what to do about it? Well, never fear you are not the only one who has dropped some serious mpg.

This article will discuss what can cause a drop in miles per gallon and what you can do about restoring it.

Hey, Did You Check The Weather?
Believe it or not, the number one reason Prius owners see a decrease in fuel economy is inclement weather. That means extreme hot or extreme cold (like we are seeing now) plays a massive role in your Prius's efficiency.

Toyota Prius MFD

In cold situations, plaguing so many owners right now, the gas engine has to run to make the heater work. If you are running the gas engine, you are using gas.

You could bundle up, drop the thermostat down to 70 and go about your business, but chances are you may only gain 1 to 2 mpg. My honest opinion is that you just need to tough it out for a month. Once the sky turns blue again, and all the ice is gone, your car should bounce right back.

Those Round Things Are Called Tires
Tire pressure, the silent mpg killer. Check your pressure every month. I do not care if the light is off or not. If you care about fuel economy you will check your pressure.

Toyota Prius tire chains

The recommended pressure found inside the driver door jam is a starting point. That 32 psi is a decent balance between ride quality and fuel economy.

If you want to boost your econ, take your psi up a bit. The extra pressure will allow for less drag on the road resulting in a better economy. I do not recommend higher pressure in the winter though, you need all the grip you can get. A suitable set of snow tires is the best bet for winter.

Hey, That Is A Cool Battery
Your aging hybrid battery could be costing your Prius to have a lower econ. A failing or bad battery does not allow for adequate gasoline engine off time. This action results in more extended periods of engine run time and lowers fuel economy.

Toyota Prius charging HV battery

A smart Prius driver knows that periodic reconditioning will help mitigate this issue. Once or twice a year, give your hybrid battery some love. It will treat you right for longer than you would expect. To learn more about battery reconditioning, check this article out here.

Do You Remember When?
Ever been so busy in life that you completely forgot to take care of your car? I have. The washing, oil changes, tire rotations, and everything in between are all part of fuel economy.

When we forget to service our Prius, this can lead to components breaking down and causing the car to drive poorly. Typically, a vehicle that does not operate well will also be one that drinks more fuel.

Toyota Prius Spark Plugs

Part of keeping clean also means a clean fuel system. Injectors, air filters, and spark plugs all need to be taken care of. Keep that Prius humming with regular maintenance. You will be glad you did when you get 45 mpg or better.

Pay No Mind To That Light On Your Dash
Trouble codes are more than just a little annoying light on your dash. They mean there is a system fault. When the car is not operating correctly, how do you expect it to get good mileage?

Toyota Prius Check Engine Light

While some trouble codes are far more severe than others, keeping the light off means your car can learn values to help it sip fuel rather than gulp it. If you ever get a check engine light, be sure to have it checked out as soon as possible and get the proper repair done. Your gas tank will thank you.

That is all for this one, folks. If you have any questions, you know where to find me. Have questions about whether to install an oil catch can or not on your Prius? Take a look here to read about it.

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Peter Neilson is an automotive consultant specializing in electric cars and hybrid battery technologies. He holds a Bachelor of Science in Automotive Service Technology from Weber State University. Peter can be reached on Linkedin and you can tweet him at The_hybrid_guy on Twitter. Find his page on Facebook at Certified Auto Consulting. Read more of Peter's stories at Toyota news coverage on Torque News. Search Toyota Prius Torque News for more in depth Prius coverage from our reporters.


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Comments

I was down 5-6 mpg and did a fuel system clean, no change. Then I cleaned the mass flow sensor and immediately got 4-5 back.