I just filled up my tank and i only got 25 mpg. Where should i begin?nnI usually get lower 30's.

 

Has there been any drastic changes in your driving habits or the weather? My car typically gets around 25mpg about town but with the weather turning cold (and the winter blends in gasoline) I only get maybe 20-23 around town and while I usually see 30-33 (2006 MCS) on the highway the other day I took a longer 90 mile trip when it was below 10 degrees and was struggling to see 30mpg at steady state cruising. Look for the obvious things before you assume there's a problem.

 

Stop having so much fun.

 

Depending on how and where I am driving, my average mpg on a tank will range from 18 mpg to 33 mpg.

 

It's probably the ethanol in the gas you just bought. The pumps sometimes indicate that the fuel "may contain up to 10% ethanol". This is done during the winter months. I have a feeling that the tank that gave you such bad mileage had a hefty dose of ethanol.

 

I've been driving my girlfriend's Scion xA (1.5L / 105hp / 2300lbs) this week and could barely squeeze out 30mpg out of it according to the ScanGauge. In the summer it didn't take much effort to squeeze 45mpg out of that car, 50mpg with some hypermiling tricks. I blame cold and gas. Primarily cold.

 

I think if your in a cold climate you can chalk it up to the higher alcohol in the gas. My Mini's mileage has dropped as well as my 2008 escape hybrid.

 

Another thing to look for is tire pressure. When it gets cold pressures drop and can affect gas mileage.

 

Judging performance on one tank of fuel is like judging the potential fitness of a life partner based on one kiss on the cheek. Dealing with numbers, you need a whole lot of them before a value judment can even be considered. Only then can you start trying to figure out how to calculate a root mean square deviation.

 

Worked for me!

 

There are a plethora of historical threads in the NAM archive that discuss seasonal dependencies of fuel mileage. Tire pressure and fuel blends are contributors, as are ECU response to air temperature, use of the defroster to keep winter windows fog-free (which operates the AC compressor), differences in driving habits, individual engine design characteristics/mods, and several other factors.

A quick analysis of these data, averaging the observations of a large number of contributors, seems to indicate that a 2 to 5 drop in mpg during the winter driving months is pretty normal.

And as Fly'n Brick implies, the variables are constantly changing.

 

did you put on a set of winter tires? i noticed a drop of about 5 mpg when i put on my winters.

 

Going through old posts and i realized i never disclosed the resolution. I had the dealer take a look at it and my rear left break was not disengaging fully cause it to drag and kill my gas milage.

 

Shoulda smelled that from a mile away. My co-pilot sets the hand break with the gusto of a sleepwalker and forgot to disengage it once. She drove it for a few blocks before wondering what the red light on the tach was for. It stunk up the garage for a week.