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 not 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.
so no spark plugs or air filters changes????? If the gap has widened on those plugs, it's going to run less efficiently. Ditto with a weak traction battery; usually discharges and recharges at a faster rate than 'normal'.
Yes, air filter changes along with oil changes every 13 to 15k miles, oil filter changed every oil change. Rotated tires also, always even wear on them as far as I can tell. I failed to state above, that at the same time I changed the coolants, I changed the ATF, All the fluids were from Toyota for my model. Yes, I see the rapid discharge of the battery, and also the rapid charge of the same, but it is not especially pronounce, to put another way, I need to actually time it to be sure it is taking longer. A diagnostic for the battery I read on a non-Toyota website is to start the hybrid system and time how long it takes for the ICE to shut off, if it runs for longer than 2-3 min, it may be failing. I called a retail battery replacement place, Green Tec,, the salesman said that it is diagnosed for sure with an OBD reader, I'd like to know for sure if this is true, I read some negative reviews of their batteries, as they did not last long or expired just out of warranty. I am concerned about the spark plugs, but I'm not an expert mechanic, not even close, I worry that I might break the plug or knock dirt into the cylinder - it's run perfectly up until now, and I don't hear any misfires. I don't trust Toyota service, and have reason not to. I only used them for my converter replacement because my trusted mechanic wouldn't do this job, as he had a contract for farming out exhaust work to a nearby exhaust specialist shop.
Is there a "How to" on throttle body cleaning? FWIW, my engine compartment is cleaner than any vehicle I'n ever owned, and no visible leaks at gaskets on the upper half of engine and no oil traces on my lower cover or garage floor.
yes, there are threads here, i'm not sure about gen 4, or if it's different in any way. there should also be youtube videos available
A misfire means the cylinder is completely DEAD - no combustion. A weak spark means partial combustion, less power - meaning more gas needed to do the same job. Isn't that what you were asking about, more fuel being burned? Ditto with the traction battery. Around 28 batteries in series; you get a few weak batteries that isn't pulling it's weight, those other batteries in the chain needs to make-up for them - ergo the faster than normal discharge and recharge cycles. I don't know if the Dr Prius app is still free, that'll scan your pack an give you an idea of it's condition. IMHO; don't do a refurbished pack - get a new one if your going to keep the car. Less headaches and hassles in the long run. That's why there's bad reviews on Green Tec; swapping out old batteries with other old batteries is a crap-shoot. It's not like a mechanical part that you can see it's too worn-out to be reused.
