2008 FX4 MPG Issues
03-09-2017, 08:46 PM
#11
Super Duper Senior Member
This is true. After changing my tire size I hand calculated my mileage. Went by what the computer said my miles were, and then checked it against mapping programs. My actual miles traveled was way off. I was getting more than a full mpg higher using the correct distance traveled.
03-09-2017, 09:26 PM
#12
Senior Member
That's not knowable. There are simply far too many variables involved in a difference of a few mile per gallon. He doesn't drive the same roads, in the same temperatures, or similar terrains. I doubt his driving habits are the same as yours or mine. Not to mention your tuning isn't factory either.
Heck if he runs winter blend gas and you live in a state where you don't, there's a couple mpg right there...
Also you have 4.11 gears (someone matched the gearing to your 33's?). Most F150s with 17"/18" wheels came with 3.73, and I've seen a couple with factory 20" wheels come with 3.55 (you can get the actual ratio from the axle code on the sticker inside your door). While certainly possible, I doubt his gearing is the same as yours.
YOUR mpg on YOUR F150 doesn't represent what he should or shouldn't get on HIS F150, other than a very broad general similarity.
Now, if he was getting 6 mpg and everyone else was getting 10-14, you'd have a reasonably good point, but in this case you may be creating expectations for him he may never reach.
I'm not sure what the actual difference a half inch would make when calculating, but you have a great point. His mpg would be lower than actual if his speedometer was not re-calibrated as the distance traveled would be shorter but the fuel consumed would be correct.
Heck if he runs winter blend gas and you live in a state where you don't, there's a couple mpg right there...
Also you have 4.11 gears (someone matched the gearing to your 33's?). Most F150s with 17"/18" wheels came with 3.73, and I've seen a couple with factory 20" wheels come with 3.55 (you can get the actual ratio from the axle code on the sticker inside your door). While certainly possible, I doubt his gearing is the same as yours.
YOUR mpg on YOUR F150 doesn't represent what he should or shouldn't get on HIS F150, other than a very broad general similarity.
Now, if he was getting 6 mpg and everyone else was getting 10-14, you'd have a reasonably good point, but in this case you may be creating expectations for him he may never reach.
I'm not sure what the actual difference a half inch would make when calculating, but you have a great point. His mpg would be lower than actual if his speedometer was not re-calibrated as the distance traveled would be shorter but the fuel consumed would be correct.
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TurnKey (03-10-2017)
03-09-2017, 10:10 PM
#13
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Your mileage should be much better. Have you tried disconnecting the battery and resetting the pcm? My 07 with 4.10s and 33s gets 14-15 pretty easily and had a high of 17mpg on the last pure highway run.
fwiw, I have new plugs, synthetic oil, synthetic diff fluid, intake, exhaust, and SCT tuner.
fwiw, I have new plugs, synthetic oil, synthetic diff fluid, intake, exhaust, and SCT tuner.
03-10-2017, 08:33 PM
#14
BAMF Club
Yes I corrected my tire size, and hand calculate, and run winter fuel (Alaska...) 4.10s were factory installed. My wet weight is also 6800lbs with the tool box and full tank of fuel.
I was just posting my results so that the OP can see that higher mpg are possible.
Colorado wasn't mentioned, which would negatively impact mpg.
hwy speeds (80+mph?) also weren't mentioned.
Here are the fuelly results for 2008 F150s. Maybe that will help show that 10-14mpg are on the low end of what these trucks get.
http://www.fuelly.com/car/ford/f-150/2008
I was just posting my results so that the OP can see that higher mpg are possible.
Colorado wasn't mentioned, which would negatively impact mpg.
hwy speeds (80+mph?) also weren't mentioned.
Here are the fuelly results for 2008 F150s. Maybe that will help show that 10-14mpg are on the low end of what these trucks get.
http://www.fuelly.com/car/ford/f-150/2008
Based on data from 145 vehicles, 7,013 fuel-ups and 2,038,550 miles of driving, the 2008 Ford F-150 gets a combined Avg MPG of 13.94 with a 0.07 MPG margin of error.
03-10-2017, 11:48 PM
#15
Senior Member
Here are the fuelly results for 2008 F150s. Maybe that will help show that 10-14mpg are on the low end of what these trucks get.
http://www.fuelly.com/car/ford/f-150/2008
http://www.fuelly.com/car/ford/f-150/2008
It shows the average is not quite 14: Based on data from 145 vehicles, 7,013 fuel-ups and 2,038,550 miles of driving, the 2008 Ford F-150 gets a combined Avg MPG of 13.94 with a 0.07 MPG margin of error.
But that includes reg cab, V6, 4.6L and 5.4 V8, Flex, Gas, yada yada...
If you filter 5.4L and SCREW it filters out all but 6 vehicles: Based on data from those 6 vehicles, 158 fuel-ups and 62,734 miles of driving, the 2008 Ford F-150 gets a combined Avg MPG of 13.27 with a 0.38 MPG margin of error.
That's not even knowing if it's 2WD or 4WD, because there's no way to filter them.. and even if you could, then what...? You're going to draw conclusions based on a sample size of 2?
EPA Estimates for 5.4L 4WD is 14mpg combined; 2WD is 16mgp. SuperCrew adds another 800 lbs in the equation.
He drove 3054 miles and used 245 gallons of gas, giving him an average of 12.46 mpg, vs the 6 from your site (2/4WD distinction not made) which averaged 13.27. If you apply their margin of error, the figures are almost identical. How does that make what he is getting "way low" OR "on the low end of what these trucks get"? What am I missing?
Incidentally, the last 3 months mine has averaged 10.92 mpg. Mine must really suck! Honestly, I from all this yours seems to be the outlier; you're very lucky to be getting what you're getting!
03-10-2017, 11:50 PM
#16
That's not knowable. There are simply far too many variables involved in a difference of a few mile per gallon. He doesn't drive the same roads, in the same temperatures, or similar terrains. I doubt his driving habits are the same as yours or mine. Not to mention your tuning isn't factory either.
Heck if he runs winter blend gas and you live in a state where you don't, there's a couple mpg right there...
Also you have 4.11 gears (someone matched the gearing to your 33's?). Most F150s with 17"/18" wheels came with 3.73, and I've seen a couple with factory 20" wheels come with 3.55 (you can get the actual ratio from the axle code on the sticker inside your door). While certainly possible, I doubt his gearing is the same as yours.
YOUR mpg on YOUR F150 doesn't represent what he should or shouldn't get on HIS F150, other than a very broad general similarity.
Now, if he was getting 6 mpg and everyone else was getting 10-14, you'd have a reasonably good point, but in this case you may be creating expectations for him he may never reach.
I'm not sure what the actual difference a half inch would make when calculating, but you have a great point. His mpg would be lower than actual if his speedometer was not re-calibrated as the distance traveled would be shorter but the fuel consumed would be correct.
Heck if he runs winter blend gas and you live in a state where you don't, there's a couple mpg right there...
Also you have 4.11 gears (someone matched the gearing to your 33's?). Most F150s with 17"/18" wheels came with 3.73, and I've seen a couple with factory 20" wheels come with 3.55 (you can get the actual ratio from the axle code on the sticker inside your door). While certainly possible, I doubt his gearing is the same as yours.
YOUR mpg on YOUR F150 doesn't represent what he should or shouldn't get on HIS F150, other than a very broad general similarity.
Now, if he was getting 6 mpg and everyone else was getting 10-14, you'd have a reasonably good point, but in this case you may be creating expectations for him he may never reach.
I'm not sure what the actual difference a half inch would make when calculating, but you have a great point. His mpg would be lower than actual if his speedometer was not re-calibrated as the distance traveled would be shorter but the fuel consumed would be correct.
03-10-2017, 11:59 PM
#17
Senior Member
Once you find your axle code, you can use this chart to identify the gear ratio.
