First of all, I have a 2012 3.7 with 4000 miles on it. My gas mileage seems to have changed pretty drastically over the last week. I have gone from averaging 21 (commute has a lot of lights) to around 17. All calculations have been done manually without the avg mpg readout (which we all know is a pessimist)

Anyone know what could be causing this? My driving has been the same I have not noticed any other changes. Could it be the MAF has been dirtied with filter oil? I installed an airaid CAI around 1000 miles ago. Thanks for your help!

 

Winter blend fuel will kill some gas mileage.

Doubt it's filter oil fouling the MAF unless you re-oiled the filter and used too much.

 

In the fall / winter your MPG will go down due to the thicker air, but also with the CAI your pulling more air and thus need a little more fuel to keep the right fuel air mix. However you do seem to have a big difference. Did you also install a tune with the CAI??

 

i have not re-oiled the filter and i do not have a tune (yet).

 

Possibly due to the winter fuel blend, also- check your tire pressures!

 

Winter fuel, my 2010 went from 28 to 24, just like last year

 

after reading into the winter fuel blends I think you guys are right. I probably never noticed it on my truck because it didn't have an avg. MPG readout (and it got awful mileage in any season)

I don't mind the lowered efficiency if it's normal, just wanted to make sure nothing was wrong. Thanks for the reassurance!

 

Are you buying the same fuel as before? Has the fuel been changed from dino-gas to "ethanol-enhanced"?

E85 fuel costs about 10 - 15% MPG....

 

Well, it won't run on E85, and you lose more than 15% running it in cars that it will run in.

 

no, i am not running E85. haha. that would be problematic.

 

I hear diesel cars get better mileage. Maybe try the green pumps.

 

oh i heard the opposite.... so i put 93 octane in my girlfriends TDI.