I have a 2016 Prius. It has always achieved excellent MPG, averaging 62 mpg over the lifetime of the vehicle which is currently 206,000 - it would be closer to 65 mpg if I had installed the blocks for the radiator from the beginning. I live in Ohio and winter took it's toll on mpg until I found this hack here on PriusChat. This fall I got new tires, I ordered the same tires as before, which gave me excellent service. I did note a 5% drop in mileage with the new tires. The last couple of tanks of gas have yielded substantial losses of mpg from around 66 to 53 mpg. The last tank, I noticed the highway mpg was very similar to the city driving mpg, which is incredible to me as it always in the past was MUCH easier on gas during city driving, in fact displaying 70 mpg frequently when no engaging in any highway driving... I'm wondering what beside tires, winter gas formulation, mpg calculation would be causing this? I drive the Prius to near empty every tank, when the 'low fuel' light comes on, I have always gotten at least 100 more miles. I always do this, driving to near empty, rarely do I fill up before this, I would guess less than 10 times I have added gas before the low light has come on. I've calculated my mileage separate from the displayed value many times and have found it to be about 2 mpg less than the displayed value consistently. This car has had 4 sets of tires, and this is the first time I've had a drop in mileage that I can recall. With this many miles, I'm wondering what I can do to restore my mileage and what it would cost, or perhaps just leave as is and continue to observe. Please share your high mileage Prius experience with me, perhaps you have an anecdote that will help me decide what to do next.
All that rain and cold snap you've been experiencing over the past month may have something to do with this? Perhaps some fuel contamination or sticky calipers? Just spit-balling here....
can you tell us what services have been performed over the lifetime of the car? there are so many things that can affect mpg's.
Historically, it's not a lot of cold or rain - I'm getting into 48 mpg on the highway, typically this level has only occurred with temps around 0 F, it was 30 F last night when I was seeing this. The services I have done myself, I did have the Dealer replace my exhaust catalytic converter and heat exchanger in July, afterward my mileage was normal as stated above. I did all my own oil changes and changed out the cooling fluids in inverter and radiator. Ran fine afterward, and the problem just happened last week, 2 tankfuls of gas, now the third one just started on the 26th. I'm guessing my battery is failing, I'm told I will know for sure when I get it scanned. The car sat for a year in 2021-2022, I understand this is hard on hybrid batteries. I haven't done the recommended services on this at all. Never had any problems until this year, over 200K miles.
