I have a 2016 cummins. I was averaging about 16.5-17.0 MPG city until November when I changed my fuel filters & the weather turned a little cooler. Now I'm around 13.0. I am thinking I made a mistake on one of my filters or got the wrong one. I am pretty sure I got the correct ones but who knows. Help.

 

You don't say where you are located but your mileage change is typical for winter fuel.

 

As the big man above said if your in an area with winter diesel your mileage will drop. I notice about a 2mpg drop every fall/winter, it's been that way since my first diesel truck in 04/05.

Area, DRW or single, rear end ratio, trans will all effect it but 2-3 mpg drop seems the norm.

 

I live in the Boise area. Normally our winters are fairly mild. This year we've only topped freezing a couple times in over 2 months. We're calling it snowmagedan. Anyway, I had a powerstroke before the Ram & didn't see a drop in the winter so this big of a drop surprised me. Thanks again. Russ

 

If your letting it warm up for a time, like you generally don't do in summer, this will have an affect.

 

...and driving around in 4WD will hurt the mpgs of course.