Originally Posted by Dooley rig 29
So bought this truck a month ago 100000km on it. Its an 07 6.0 . It had awesome power and decent fuel mileage,5.6km/L. 10,000 k later its lost some power and fuel mileage was down to 5.3 ,so i replaced the fuel filters(yes there ford) and had ALL my power back but NO gain in fuel mileage, now 3 days later its lacking a bit of power again and mileage is down to 5.2....Filters are still clean, fuel and driving habits are the same. i run diesel kleen every other tank. from the last few hours of reading i am leaning towards bad ficm or failing injectors.... any thoughts from the techs? oh btw thats about 12.3-12.4 mpg ...sorry im in Canada guys
my 06 kingranch with 37's chiped and done to the nuts gets better mileage than this :S
As I was reading your thread I started thinking about the usual things that can rear their ugly head with the 6.0L and fuel mileage - - - until I got to your signature and saw that you're running 37s. I suspect those are your problem, perhaps in one or two ways. 1) they weigh more, have a higher rolling resistance, and likely have a larger cross section than stockers - meaning lower fuel mileage. 2) the truck may not have been recalibrated for the larger tires, meaning you're covering more ground than your speedometer/odometer are indicating, making you think your fuel mileage is less than it really is.
Lastly, is the fuel mileage you quote hand calculated or from the "lie-o-meter"? The lie-o-meter is notoriously over optimistic on fuel mileage...