I'm Losing bars on my Gas Gage, Am I losing Gas too?

"how do I monitor this?"

Reset the trip odometer when you refuel. Then the next time you refuel, log the miles driven vs. the number of gallons driven, and divide to determine mpg. Do this a few times to see what the long-term average is.

 

If you drive the car regularly you should have some kind of idea if is taking more or less gas to fill up. I just traded in my 2008 and there is the issue with the bladder in the gas tank in cold weather, do you know about that? I will tell you if you don't know. The second generation Prius including 2008 have a bladder inside the gas tank and is very stiff in cold weather and you can't get as much gas in the tank. When summer comes it is more pliable and then fills up properly. It may be as much as say two gallons difference. They did away with the bladder in later generations I heard.

I see you are in Chicago, I have the same weather you do, I live in NW Indiana.

 

There are several more issues that affect gas mileage in the winter, some that every car has. Mechanical parts in any car don't move as easy in the winter, oil and grease is thicker then you have snow and ice or whatever is on the road and even the tires don't roll as easy so there goes your gas mileage. Then there is the main hybrid battery in your Prius. Batteries don't perform as well in the cold, they have a sweet spot as far as temperature, not too hot and not too cold. When it warms back up in the spring your fuel economy will increase again. One thing I almost forgot, any time you have yor heater on it will cause your engine to run a lot more in the winter. Lots of things cause bad gas mileage in the winter but the Prius has a few quirks of its own.

All this doesn't mean there couldn't be something wrong with your car. Do the math like the other poster told you to do and then you can work from know facts. Good luck.

 

You are worrying about the wrong things.
The ONLY things that count are the number of miles driven and the amount of fuel that it takes to do that.

From your posts, it appears that you don't really know the history of either of those numbers so it is possible that the ONLY thing that is wrong is the additional fuel needed to keep YOU and the car "warm" when the weather is extremely cold.

It is possible that the "bladder" problem is not allowing you to put as much gas into the tank at each fill......but that does NOT really affect your "miles per gallon", it just means you effectively have a smaller gas tank and need to fill more often.

 

Our 2006 is lucky to get 6 gals on a fill up now in cold weather.
MPG is well under 40 for short trips in cold weather, so we are lucky to get 250 miles range.
But 250/6 is 42 MPG so that's what we have at best.

 

how many miles on your car?

 

165k miles last time I looked

 

sorry, i meant the o/p. yours is dong great though!

 

IF.....you would make proper use of the Quote feature, that wouldn't happen.

 

that would take all the fun out of priuchat.

 

YOU need another hobby to take up some of your time.

 

i know. retirement has left me with a lot of holes to fill, especially when it's zero outside.

 

This bisco is way too funny in his comments