boltzie42

For the first 8000 miles, I was averaging approximately 15.5 mpg to and from my office. I have the 5.0-V8 engine in a 4x4. For the last 1500 miles, my average has decreased to 13.5 mpg. I checked the air filter and the oil is good. Could the catalytic converter be going bad and would this decrease the mileage? Is there a known issue with the 2011 F150 5.0-V8 engine losing mpg?
I'm running the exact same route so nothing has changed by way of types of driving that I am doing. Obviously 4WD will decrease it, but it hasn't been used much at all with this mild winter in Ohio.
Thanks.

p38fln

Cold weather will decrease mileage - its pretty well documented for all vehicles. Even if you don't wind up with winter fuel, MPG will still go down. Something to do with more oxygen in the colder, denser air, along with having to push through the colder, denser air as you drive.

TJPlatinumEB

Cold weather plus crappy winter fuel blend equals a loss of 1-2mpg in the city during the winter.

I normally average 17mpg on my normal work trips and in the last few months I've average just at 16mpg or just under that now. Perfectly normally for cooler weather and the junk fuel blend we get in winter time.

mello_collins

Also air up you tires a little. Check them in the morning be for you start out. I would bet your cold tire pressure is down to around 30-32psi.