I've got 33K on my 05, 5.4 Lariat. The mpg was around 17-18 now with the same driving habits it's gone down to around 11. I'm going to change out the air filter, what else could cause the mileage to tank like that? The truck is bone stock, no mods. thanks,

 

Hey ,
Same problem, my truck is a 04 5.4 fx4 super crew, excellent condition, is not around 11mpg with easy driving, even high way driving. Bone stock, but has a k & n airfilter system , but that was on there when I bought it and it had decent gas mileage then?

 

My mileage always goes way down in winter, but this winter in particular, since we've had record snowfalls and some cold temps. I'm probably doing no better than 11 or 12 mpg, though I haven't really measured it, I'm just estimating. Definitely, though, it is worse mileage now than it is in summertime. Mine is an 04 Supercrew with 42k on it. Also bone stock.

 

don't know the answer, but my truck (26k miles) has rarely-never seen better than about 13.5-14.5 max on the highway- it averages about 12-13 and 10-11 city
regardless of mod status...i don't worry about it- if i wanted gas mileage i would have bought some economy soap box.
in the winter (nov thru march up here) its usually about 1 mpg less due to the increased ethanol content in the winter-blend gas

 

yep mines taken a dive as well from about 14mpg to 12.2mpg I assume its just the winter gas..

 

My 05 Scab 5.4L FX4, has rarely gotten over 12-13 mpg's and my truck is stock to the bone as well with only 7,500 miles on it; the only things I have done to my truck have been to try and better my mpg's I have installed a K&N air filter and a tonneau cover.I drive like an old man I dont race people or see how fast I can get from one stop light to the other. I like how FORD advertised on the window sticker that these trucks would get 14 mpg city & 18 mpg hwy. I would have to say that is the biggest line of B.S. I have ever read, and very nicely falsely advertised. I would do anything to get that kind of mileage.
I have always been a Ford Man but the Chevy's and their honest advertised mpg’s are really starting to look good. Very sad too say.
I bought my wife an 07' Tahoe and that thing gets awesome mpg's I recently drove from north dakota to texas and I averaged 24 mpg's.

About the only thing that I have done that has improved my mpg's ever so slightly is using Castrol Syntech w/ K&N oil fliter, the other plus is that it gave my truck a little more pep in her step.

 

Ummmm you do know that neither Ford nor Chevy post mpg numbers. These are derived from the Fed who tests the vehicles. Also as for your wife's Tahoe - it aint a truck. Diff aeros, Diff weight, Diff gearing. What can the Tahoe tow? I guarantee it isn't 9900 pounds.

If you want better mpg, easy on the gas, use cruise... make sure tires are properly or slightly overinflated, good air filter, spark plugs are clean, etc.... Prob the bigest thing and most overlooked is proper psi in tires. That alone can add 1-2 mpg.

I have always gotten 14.5-15.5 mpg mixed driving on my Screws. I get a high of 18-19 on the hwy and a low of 11-12 towing 8K pounds at 70+ mph. Or maybe 13-14 driving in 4x4 all the time in a snow or off road. I think this is very fair for a truck like this.... Look at all the other large trucks, they are similar mpg or sometimes much worse.

 

ALL gasoline is worse for MPG during the winter. That will reflect some of your problem.

You may need to clean your filters in some cases.

but I can almost guarantee 9 out of 10 of you are simply changing your driving habits. When people first buy new cars and trucks they tend to take it easy on them. As time goes on, they don't baby it as much, and they pay for it at the pump.

Try making a serious effort to lower those RPMs and then check your results.

And fwiw, I get 12.3 consistently with aggressive driving. So you guys aren't far from the norm.... it;s a TRUCK, not a 4 banger car.

 

As far as chevy's go, i traded in my 04 chevy silverado, z71, extended cab, and it always did really good on gas mileage. They told me my ford would be about the same....not even close, its horrible. I have a tonnea cover on mine also, and i don't think that hellped either. It's insane. When a good town is just down the road (45 minutes), I don't even think about driving my ford, i take my little gas saver I bought to drive back and forth to school. The ford costs way to much.

 

I had the same problem. Did everything to correct with no change. Then I checked my air pressure. 24lbs all the way around. Filled to 34 and gained
1 1/2mpg. Funny how the things you think least of can be so important.
I average around 12-13 around town/to work and 15-16 freeway. I also have two speeds - fast and stop. I'm hard on throttle, hard braking, 80mph+ freeway etc. I think I'm doing prety well for a 6000 lb. truck. That said my 06 Mustang Gt gets 24mpg at 80-100mph LOL
Sam

 

Mine has 30,000 miles and I still average 17-18 mpg, regardless of what time of year it is.

Something must be wrong to cause that much of a decrease in mileage.

 

You're very lucky. I've read three tests from magazines and newspapers. They tested a 6.0 Denali on the interstate and they got 14.1 on the trip. Another tested a GMC Yukon with 5.3 (Motortrend- http://www.motortrend.com/roadtests/..._gmc_yukon_slt and overall, they have averaged 11.9) and yet another tested a new silverado with the 5.3 (USA Today- http://www.usatoday.com/money/autos/...o-sierra_x.htm ) and they averaged 11.6 in city driving.

 

When running my summer wheel tire combo (325/60/18 on 18X9 Helos) I average 14mpg mixed city/hwy and average 16.5 when running all hwy. But when I put my stock wheels/tires (275/65/18 AT/S's on factory FX4 wheels) back on I have been getting 15.5 mixed city/hwy and 17.5 on all hwy. I had an all time best of 18.7mpg just before christmas. For some reason the "winter fuel" doesn't seem to affect my truck at all. But my 05 Focus ZX4 that is a different story, the mileage on that has dropped from 30-31 mixed down to 25 mixed. The little Focus just hate this fuel blend....

 

My wife’s Tahoe weighs more than an F150 Scab and has the 5.3 with practically the same gear ratio, no it won’t tow 9900 lbs but it comes damn close, and I’m pretty sure my spark plugs are clean being that I only have 7,500 miles on the thing, and I am running a K&N air filter and I maintain the proper psi in my tires at all times, kind of why I bought an air compressor. I maintain my vehicles extensively. I also don’t hammer down on the throttle. As for the feds and the mpg’s I know they do that but ford should give them the worst case vehicle and not a reg. cab 2wd with the 4.6L, because that is what they used to configure their analysis according to the USDMV.
Just curious, did you even read what I posted?

 

Where did it ever state that a reg cab 2wd with a 4.6 was used to determine all EPA MPG figures? Don't pull facts out of your *** and don't blame the companies, blame the system the EPA uses is all the previous poster is saying.