I bought an 05 FX4 supercrew with 18" wheels and pretty much all the options (I think ) 3 months ago. Question is, I'm getting about 10 mpg around town and 13 on the hwy, and this is driving like a granny trying to get good mileage. It also seems sluggish with not a whole lot of power. The build date is after the date I've seen for the flash that's said to help this. Should I bring it in to have the dealer take a look due to the low fuel economy and perceived slugishness?

 

There may be a calibration upgrade regardless of the build date of your truck. Might be worthwhile to visit your dealer.

 

Might be worth a trip to your dealer. My 05 FX4 SC gets about 14-15 city.