usafstud

what tires are you running? A/T, mud, and etc?

Collin

Made me laugh..so i figured i'd be a smart*** Try changing the trans/tcase/diffs fluids. If I remember correctly I picked up 2-3mpg after doing that

3point5

Can you look into your mass air flow sensor? Possible (gently) remove it and clean it? if you're not throwing any CEL then it probably functions within specification but may be a little dirty which would send incorrect signals to the ecu...

Moose08

Summer runs 18" svts w/ 285/60-R18 Discover HT+'s since ive had truck.
Winter 17" 275/70-r17 mtrs.
Summer and winter mpg was 1-2 at best difference. 100% its not tire size/weight issue.

lol ya all good i did change all driveline fluids at 110k

Moose08

Ive cleaned it all up this weekend going to see what i get this week

Moose08

sigh this thing is pissing me off, new MAF, new 02s, computerflash, new fuel filter, good fuel pressure, trans fuild, tcase, and diffs.

as much as i hate chaning plugs on this thing, going change plugs again (changed them back in 08, and replace every COP that i havnt since 08

ibd2328

iTrader: (2)

Whats your elevation? Could be the density of the air.

I have a similar truck, 03 Supercab with the 5.4 and I only average around 7-8 town and 11-12 highway. I typically average well under 300 miles a tank (23 gal.).

Of course 305/70/17's at 70lbs a tire don't help much.

comfun1

I have 130k and my mileage is down a little. I notice this in all of my vehicle when the mileage gets high. My feeling is it is the gradual decline in compression caused from wear in the cylinder and rings. It may not be enough to cause oil loss but it does decrease the power which we compensate for by an ever increasing pressure on the accelerator be it ever so slight.

Moose08

I lived in the same area as when i baught the truck to elevation hasnt change, and your tires i bit bigger then mine 285/60r-18 is my street

I havnt checked comp yet, ill do that while i have plugs out, Ive had many cars with 150k+ and the gas mileage was the same at 50k maybe 1-2 diff at best, but ill check

Tonelocs47

Have u tightened ur header bolts lately or do u hear a slight ticking at all when u gas it? I didnt do it for a long time and my truck started losin a couple mpg and some torque, found a couple leaks between the headers and there gaskets, retightened everything an now i got all my mpg and torque back now