getting 21mpg

Since you said you got the car with a partly filled tank, you need to wait until you know how many miles were driven on a full tank of gas first before figuring out miles per gallon. So if you haven't filled up the tank yet, then you want to pay attention to the miles traveled between when you fill it up next and the time after that. Then divide by the number of gallons you got in the second fill-up to give you a usable number. Or if you don't want to do the math yourself but can save numbers, sign up for Fuelly. Enter in your odometer reading and gallons of gas purchased and they'll do the math for you. They also keep a running tally of your cumulative miles per gallon.

 

Or do both.

 

Ok, that is a bit clearer. It is not unusual to to get low readings initially but as the tank approaches empty (from Full), it will balance out to be a more reasonable average. As a new Prius driver, you still should be able to get 45 MPG to 47 MPG without trying. I've noticed that if I get a good reading initially, it carries on to be good, but if I get a bad initial reading, it can generally be quite hard to peg it back. YMMV. (Doubly hard if you have a lead-footed co-driver.)

As has been noted, you need to fill up to full first, then the next time you fill up you can start "doing the math".

 

Also be aware that fueling nozzles at gas stations can have slightly different shutoffs so the true test of a car's MPG is over several tanks as one tank can be a short fill and the next a full fill and they balance out over time. I think I've varied 15MPG fill to fill but it always seems a unusually high MPG tank is followed by a low one but the long term average is remarkably consistent.

 

Did you enter the data on Fuely too?

 

Just looked at your Fuelly page. You got a complete 11.9 gallon fill of the tank? That's amazing! I typically fill my tank when there's one square left on the fuel gauge and the most I've got so far is just over 7 gallons, presumably due to the fuel bladder.

 

Link?

Or maybe I'm not seeing fuelly icon? I'm viewing on a phone just now.

 

Prius (Toyota Prius) | Fuelly

 

Being the first entry, all that 11.9 gallon entry is doing is indicating that on that date the tank was full and what the odometer read. The 11.9 gallons will only slightly affect the long term numbers putting the first entry that way.

Actual calculations will begin when the second entry is made and will calculate based on those gallon figures, not this first one.

 

you have a rubber bladder inside your fuel tank. it affects how many gallons you can put in. don't travel any miles after the gas light starts blinking.

if you want to improve mpg's, learn how to hyper mile.

 

there are threads here on accelerating inside the efficiency rpm curve of the engine. counterintuitively, easy on the gas wastes fuel.
also, you should learn to pulse and glide. holding speed with the accelerator also wastes fuel, because again, the engine is not operating in the most efficient rpm range.

i think the oem plugs are iridium. how many miles on her, are you up to snuff on maintenance? is the 12 volt battery strong? could your hybrid battery use some reconditioning?

 

Model Years 2004-2009 are notorious for a fuel tank that will not fully refill, so driving range is shortened. Without keeping track of how much you put in, you simply can't tell if it is coming up just 1 gallon short, or 5 gallons short.

Refill NOW! This era of Prius is notorious for lack of fuel margin at this point on the gauge. While many will go a long way after the final low fuel warning -- that last bar starts flashing -- a significant number will go dry almost immediately. A few even go dry with two bars showing. Don't assume you have any additional range until you test it, under conditions that won't be a serious inconvenience if it stalls for lack of fuel. And until you learn how to not drain/damage the traction battery or lock out the ignition and need a tow to service.

45 is the EPA rating for our year, so that is normal. 64mpg and 700 miles is exceptional for your year, and requires both expertise and great conditions. Don't pay attention to what 2010+ models are getting, your car won't match them.

You might get 100 miles. Or you might stall before that light even starts blinking, especially with the rubber fuel bladder in your model year. Get fuel NOW!!!!, put off any lower fuel experiments until you better understand this particular car, see above.

Before worrying about hypermiling, go through the list of common MPG issues here. Once this list is cleared, then go after the hypermiling.
Fuel economy complaints/queries? Please copy, paste & answer these questions, esp. if you're new | PriusChat[/quote]

 

Yes, in a Prius it is more efficient. As is Pulse and Glide, over standard ICE powered cars. To put some quantitive numbers around slow vs quick acceleration, aim to accelerate at the rate of 19 MPG down to 10 MPG (if required). A good way to get a feel for the acceleration to aim for is (if you have it), to use the cruise control to accelerate and observe (on the consumption screen) what instant MPG is when it accelerates from, say, 40 MPH to 60 MPH.

The ICE is running.