Poor Fuel mileage - typical?

Welcome to Prius Chat Suzanne.

Drop the tires to 40 PSI for safety. Usually you run the fronts 2 PSI higher than the rear. I run 40 front and 38 rear in summer and 2 PSI higher in winter all round.

Your mileage is about "normal", if mileage could ever be "normalized". It takes a lot of effort to get better mileage, especially in winter, even though it's not cold where you are. Some come by it naturally and will tell you it's easy. It isn't for others.

You could try having the engine air filter changed. A dirty one can effect mileage and it's a relatively inexpensive fix. If you were in last summers fire areas/smoke both it and the cabin filter should probably be changed.

The 3rd gen Prius tends to estimate higher mileage than you actually get so that is normal.

 

congrats and welcome!

the first thing you should do is search for maintenance history to make sure the car has been properly serviced. you can sign up at toot owners and enter your vin.
although there is nothing major until 120k, you should check the air and cabin filters, 12 volt battery health and oil level.

a major player in mpg's is tire brand and model. since you are at 100k, someone might have installed cheap high rolling resistance tires.
lastly, trip type, driving style, weather, seasonal gas and topography all affect mpg's, and the margin between 30 mpg and 60 mpg can often be attributable to all these factors.

there is no such thing as a tune up in a prius, but there are items not mentioned in the maintenance manual that can be looked into, once you have checked all the low hanging fruit.
all the best!

 

Those are three calculated tanks then, and that's the range? Was the latest tank the 42 mpg? The low one, if the first, could be due to vagaries of the fillup when you got the car. I would give it a few more tanks, just to see where the numbers stabilize. It's good btw, that you're calculating, the display is fairly rose-tinted.

I'd chime in, bring your tire pressures down some, 50 is bone-jarring, might be reducing traction/grip, though I'm not sure. Try somewhere between 38~42? I set ours all to the same value, not sure of the import, Toyota's instruction to have a few more pounds in the front.

Again chiming in: it could be tires with high rolling resistance. Can you check what they are, make/model, and post? The more complete the description the better. Often posters will say "they're Michelin, or Goodyear", which doesn't really nail it, lol.

Air filters, engine and cabin, are worthwhile to check, if only to get a sense of of the car's condition/history. If the engine filter is only slightly dirty, I would not have high expectations that a new filter will improve mpg. It might actually drop it slightly. Cars are computerized, monitor air flow and tailor fuel injection accordingly. A slightly dust filter might actually give better fuel economy, sort of reducing the engine size, if that makes any sense. Anyway, doesn't hurt to check them.

Judging from the time you've had the car and number of fillups, you're likely not doing a lot of short trips? That's one thing that's hard on miles. Also good to consolidate trips.

The "jerk when it shifts itself" could be nothing, or something in the transaxle. Maybe check it's history, see if the transaxle fluid has been changed. If it's not possible to ascertain, or just to be sure, wouldn't hurt to get it changed. It's NOT on the Toyota proscribed maintenance, but dead simple. Done professionally it shouldn't cost over $100. 4 quarts of Toyota ATF WS fluid is more than sufficient. You simply drain the old fluid, reinstall drain bolt, add new fluid through the fill bolt (with the car level), and the level is right when it starts overflowing. I'll attach a Repair Manual Instruction. This is basically a preventative maintenance, won't "cure" an underlying issue, if there is one, but doesn't hurt.

Check the engine oil level on the dipstick, make sure it's between the marks, preferably near the top mark. Was the oil changed recently? For easiest checking: remove and wip the dipstick, and wait say 5 minutes before reinserting for the check. The Prius dipstick tube is prone to draw up oil when the dipstick is removed, and waiting gives it a chance to drain down.

There could be an issue with brake drag, and this is something that could definitely lower mpg. The rear brakes in particular are prone to disassembly after maintenance, in a way that causes uneven wear and extra drag. Feel all wheels immediately after a drive, see if any feel hot, this would be a tip off. Also, with the rear off the ground and parking brake off, definitive check would be to spin the rear wheels. There's a slight amount of drag inherent with the rear disc brakes, but it should be minor: the wheels should easily spin one or two revolutions.

 

This questionnaire covers most of the common issues:
Fuel economy complaints/queries? Please copy, paste & answer these questions, esp. if you're new | PriusChat

The biggest thing missing from that post is brake drag from sticking calibers or pistons, something that is more likely on older cars.

It would help if you could describe typical usage, including speed and distance per trip.

 

The first thing that SHE should do is drop the tire pressure back down to something under the maximum safe setting which is shown on the tire sidewall; probably 40.

Then one should not take a wild swing at things that you really don't understand......like maximum tire pressures.

And of course there IS such a thing as a tuneup with a Prius.
Plugs, throttle body cleaning and EGR service comes to mind.

And the first thing YOU should do is change that ridiculous signature that you have.

But I think the numbers are well within a "normal" range, especially in the winter.
To get a good feel for the actual mileage, the calculation should be made over several fills and several weeks......minimum.
Calculating each tank fill is often inaccurate.

 

I just passed the one year mark with the 2014 that I purchased used. I was expecting 50+ MPG right out of the box, so I understand your concern.

For highway mileage, a very normal and HUGE factor not yet mentioned is speed. There are charts in various threads on PriusChat showing a pretty steep curve and direct correlation between higher speed and lower mileage. I came to learn that the 37-40 MPG I was getting was perfectly normal for the highway speed I drive. For me, the time savings is worth the extra fuel cost, although with gas prices rising 12.5% over the past year, that may not always be true in the future.

 

If you are doing 65+ mph, you will not get great mpg in Winter, do you always take your foot OFF the gas pedal on downhill rolls? Do you race up hills? Do you turn off, or down, the heater, defroster? The really efficient heater is the seat heater, use that as much as you like. Remember speed is the greatest inhibitor of excellent mpg. Definitely clean the air throat and sensor, with 98000 milesl
that’s overdue.

 

Is Nevada City a very hilly mountain city? That could cause your mpg to go down quick.

 

Suzanne, what year/make/model did you drive prior to the Prius and what was your average mpg on a tank in the winter?

A good test would be taking a long highway trip with the cruise control set at 70 mph or lower. Set the tripometer after the engine is warmed up and stop it after getting off the highway (100 miles or more). You should get over 50 mpg on the car's tripometer for the trip. If you do, then driving habits and conditions will play a big factor for your lower mpg.

 

Tire brand/inflation, air filter, engine oil type, load in car, outside air temperature (OAT), hills, winds, aggressive acceleration, high speed travel, snow, rain... the long list of things that can affect MPGs. Hopefully your Prius wears low rolling resistance tires, uses the proper weight ( 0W20 ) high quality synthetic oil, a clean engine air filter with a clear intake plenum, and using a top tier gasoline brand. At 98,000 miles, new spark plugs and wires could help, too.

 

Trips of 3+ miles at low speeds get great mileage. For a 1 mile or less trip the engine will not be able to complete its warmup cycle, hurting mileage. These short trips may e what is hurting your mileage.
The Prius is designed primarily to be a low emissions, efficient vehicle. The engine, once started works to get to its most efficient operating temperature as quick as possible. The great mileage of the Prius is really a secondary goal as part of efficiency,

 

This. The 3+ miles figure might be debatable; I think it might be a bit higher. Unless maybe it takes you 20 minutes to go that 3 miles.

 

Before these trips, set either trip A or trip B to 0 and record the mpg for a round trip. Again, use cruise control if possible as it helps to take the human lead foot out of the equation. You should average well over 50 mpg for these trips, depending on the number of lights and if the engine is warmed up. Even if you don't track it with your tripometer, the dash will display your mpg for each leg of your trip after you turn off the engine.

I asked about the mpg for your previous vehicle because many people that will average below EPA estimates for their previous vehicle will also do so with the Prius. But since the Prius starts at a much higher number, the over mpg will still be improved.

 

Prodigy place is spot on with his/ her observations.
A one mile trip is probably less than is needed to get the ICE into closed loop operation. The car is in a warm up cycle most of that time, if not completely. The same thing happens on the return trip. One can not expect fuel consumption to hold up to manufacturers estimates under those conditions. It just ain’t gonna happen.

 

Yep, and this would have been the case with her previous ICE cars, too. IMO, the plug in Prius would have been a good choice.

 

I'm from that county and know those hills. Those hills will kill your mpg efficiency. Don't do the cruise control test for 30 mins there either to get a consistent mpg reading, engine will rev too high. To get a better measurement, the next trip to Roseville or Folsom, reset trip a or b mile reading and drive around those town for a much more accurate reading of mpg.

 

Plugs yes, wires no: there are individual ignition coils at each spark plug, and just a regular wiring harness to each.

 

suzanne, it sounds like you have hit the perfect storm for bad mpg's.

sounds like you are on the right track, but the tires may be a problem, no way to know how many mpg's they are costing you.
short trips are a killer as pp mentions above. not much you can do about a commute, but if you can string together other short trips, that will be helpful.
the good news is that short trips hurt non prius even more.