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.

 

Probably due to winter gas.

 

^ that and when fuel is cold it doesn't burn as well, the vapors are what burn not the gasoline itself. heat+fuel=evaporation. Evaporation+spark=combustion. at least thats what i have been told, but i can believe it. the vapors burning that is.

 

You may lose like one maybe two mpg's at best because of winter fuel based on my experiences in a similar climate like yours.... may want to take it to the dealership.

 

Mines been the same way, 18 down to 16, winter gas

 

Checked tire pressure lately?

 

Cooler temps and crappy gas.

 

Been using your remote start a lot lately?

 

Ive averaged 3 mpg loss during winter in my last 4 time vehicles. Warm up time kills me, truck is just getting warm when I get to work.

 

Winter gas, long idle times, cold temps, cold oil, cold bearings, cold tires - everything is reluctant to spin freely.

check your tire pressure as it drops significantly during the winter months.

not sure how cold it gets there but use your block heater if you have to.

 

X2

 

I agree with everyone else that winter gas makes mileage take a hit, but in my experience I see differences between brands of gas. (I imagine it has to do with the amount of ethanol in the gas.) In my area the worst mileage I've experienced has been on Citgo. My best average mileage comes with Hess, about 1.5 mpg between the two. There's also a lot to be said for cold and warm up time. I am lucky in that my truck is garaged and usually a "cold" start is around 50 F, so everything isn't frozen solid.

 

Do we get winter gas here in Texas too?

 

Tell me about it man..
Im over in PA and my eco is only getting 9.9mpg in town right now!! thats with my new tires but still....im about to take em off...

 

We must because my mileage went down 1-2 mpg since about November. I'm averaging 17 mpg in town on my Eco SCREW 3.15 2wd...And that is mostly to and from work 19 Miles each way. average speed about 40 mph with 2 school zones and about 15 traffic lights....