My Worst Gas Mileage Yet!

I would start by checking your tire pressure. I would set it up to at least 40 front 38 rear.
Also if you have been driving in cold or bad weather lately that seems to adversely affect my mileage.

 

There is not enough information to even speculate on what might be going on. For example, previous tanks? Regular route? Unusual climatic conditions? Same fuel? Pump calculated or MFD? Recent maintenance?

Bob Wilson

 

Some things to consider.....

1) Over the last few weeks, we've had some of the coldest days we've had all year in California. There are numerous threads about cold days reducing overall mpg since you need to have the Internal Combustion Engine (and catalytic converter) warmed up prior to the ICE shutting down and allowing for best mileage. Run the heater to keep warm, the ICE runs longer (as the hot air is coming from the engine compartment).

2) We just got through some of our worst rainy/windy weather that we've had all year long. Again, there are numerous threads discussing the effect both wind and rain cause with mpg's.

3) The colder weather will cause a decrease in overall cold tire pressure, you might want to recheck and reinflate as necessary.

 

I noticed an increase around 5K miles after an oil change and a re-alignment. Have the alignment checked. Mine only had one wheel off, but it made a difference. You are entitled to one under warranty within the first year. Have you reset the MFD display yet? If not you are probably doing better than it shows. Do you have a lot of "stuff" in your car? The extra weight made a difference when I was lugging around stuff for a volunteer group I was working with. Getting rid of that helped. I also saw some improvement when I blocked just the top of the grill.

My DH gets 37 mpg on his Gen I Prius, but refuses to drive any differently that he has with other cars. He tends to have a heavy right foot.

I think after 5K or 6K miles you will see some improvement.

 

I have the same problem. Just bought a 2008 Prius here in DC, and after 300 miles the average remains at 37 mpg (city driving only). Maybe the car is defectuous...

 

Location? Temperature? Type of city driving?

We need just a tiny bit of information to pose even a guess.

Tom

 

How did your previous car perform over the same routes in relation to the EPA mileage?

If it is your worst tang stop doing the things you introduced to your driving technique for this tank and revert to past practices.

 

One other point that hasn't been mentioned - this tank may have filled more than others - different gas station perhaps, or maybe you filled on an unusually warm day, so the bladder accepted more gas. Or the previous tank was underfilled, so you didn't go as many miles on the tank as you will on this full tank. Did you have unexpectedly good gas mileage last time? I usually look at the 3-tank average to be sure of any trends.

 

Okay, I didn't read this one. Disregard my previous post. MFD doesn't rely on how full the tank gets. Seems to me you have a commute of less than 5 miles?

 

How long are your trips? Short trips will yield lower MPG especially in cold climates. As others have stated we need more information please.

Gabe

 

Give it time. My first tank was 40.1 mpg, but 20K miles later, the car's lifetime average is 48.9 mpg (and that's after a bad winter, it will definitely improve with warmer weather, the average should top over 50 mpg again this summer).
City driving isn't as important as distance of trips. The first 5 minutes the engine is cold and doesn't run efficiently. The next 5 minutes your mpg often doubles, so if your commute is less than 15 minutes, your mileage will never be stellar. But your gallons per month will be very good, and that's the final measure.

 

There are so many factors involved here it is hard to say. The one factor I have found to be the worst is the wind.
My typical commute is about 10 miles each way mixed city/fwy driving. It takes me about 15-20 mins on the commute. I average around 50 mpg.

Recently, I took a road trip from San Diego to Sacramento, where I averaged somewhere around 53 mpg on the way up. On my way back, on the first leg of the drive, the headwinds absolutely killed my mileage. I kept looking out my back window looking for fuel to be spraying out. When I stopped for gas (even before the monsterous climb up the grapevine) my mpg for the 300 miles stretch was about 36. I have never experienced such a significant decrease in any car.

Blaze

 

A new Prious owner has so much to learn! Driving slow is one of those things! How does not resetting the MFD affect the mpg reading?

I am halfway through the second tank of gas. First tank gave me a little over 41 mpg. Current fillup is giving me 48.8. I have had to drive as fast as 70 mph a couple of times, but not for long, so folks sure like to ride my bumper. I get lots of dirty looks, fortunately I can't hear what they are yelling as they whiz past me.

I am learning a lot about the Prius from the members on this board. Thanks, everyone's driving tip are appreciated. One habit I have to break is to stop reaching for the key after I turn the car off. Guess it just takes time.

Anniee

 

Get drive slow out of your head, drive smooth and brake early and soft. Better still, lift your right foot early enough to stop without the brakes.
Accelerate as hard as you like but leave some room in front and obey speed limits. You don't need to be a mobile road block to get good economy.

 

Hi Anniee,
Welcome to PC and enjoy your new Prius. I prefer to reset the MFD readings after each fill up. To keep historical data I log each tank data into a spreadsheet and calculate my lifetime (weighted) average in the same spreadsheet.
This method gives you nice tank to tank progress whereas if you don't reset the MFD mpg reading your current tank results are diluted in the lifetime results.
Gabe