I feel like I get better MPG when my tank is fuller, any thoughts?

i used to, but then i measured it, and found i was being seduced by my own feelings. it turns out, under laboratory conditions, you actually get better mileage on the second half of the tank due to reduced weight.

 

The weather may be more of a factor as to why it feels that way. The prius likes its mild-warm weather, and once temps start dropping below 60F or so, it starts to affect the mpg, especially if you need the heater as well.

While grille blocking and engine block heaters will help to mitigate this, expect a roughly 10 percent drop in mpg in cooler/colder weather, especially if you live in an area that gets snow.

 

please stop using four letter words!

 

okay?

 

$now.

 

What causes you to "feel" that way ??

I experience a lot of "feelings" that have no resemblance to anything real.

 

Staying below half a tank of gas on a regular basis could possibly dry out your sensor in the tank and that could become costly.

 

Wrong... wrong... wrong... The only thing that will happen if you run the car to close to empty is that the fuel in the tank won't be able to cool the fuel pump as effectively. Driving your car between 1/4 and 1/2 will result in absolutely no difference than somebody who runs their car between 1/2 and 3/4. Absolutely no difference. Running it until the Flashy light and the E comes on will result in the same difference. It's when you push it past that that you "could" have an issue.

 

Sometimes I feel there are inconsistencies in the MFD readings. Sometimes I notice a big tick down in MPG after I fill up on the highway, which makes no sense (multiple steady states?). Bottom Line I don't really trust the MFD for MPG.

 

i feel like the engine has more power right after i fill up.

 

Unless you can get a tanker to fill you up on the fly, it makes perfect sense.
ESPECIALLY if you are looking at one of the indicators that automatically resets at fillup.

In order to fill, you must enter some stop and go traffic.....even if it is only for a half mile or so.
Your mileage will suffer a bit long term and it will look really bad if the counter is reset.