GreatWh1te

I'm really not wanting this to sound like another "I have crappy gas mileage, help me" threads, but its going to anyway.

I have a 2005 F150 Lariat Screw 4x4, it has the 5.4 3v engine in it.

I've done the following mods:

Gotts Mod
Super 44 Flowmaster SI/DO (Cat Back)
Leveling Kit
I also have a grille guard.

I have 285/75/17 (Or whatever the stock rim is, I went up one tire size I think) Nitto Terra Grapplers.

*I've done a small amount of searching, and the mpg is low for this truck, some blame the ethanol, others say buy a focus. I'm not expecting 20mpg, I just didnt expect as low as im getting.

Ok, so here's the numbers:

Highway: 13-14.5, Driving 63-66 mph
City is 9mpg-10mpg

I do mostly hybrid driving, seeing I work in the city, but live 8-9 miles out of the city limits. Even with the flowmaster, I dont drive with a heavy foot, as the MPG suffers even more.

I do haul occasionally, and on our 3 digit temperature days here in east texas, you can tell this truck is suffering.

*I also removed the gotts mod, I saw no benefits from having it after 1000 miles, and it would have voided my warranty if I had to put it in the shop with it in.

My questions:

1. Does the leveling kit cost me MPGs due to aerodynamics? if so, its coming off.

2. Does the grille guard affect MPG? Air resistance? Idk, I'm thinking of anything here.

3. Does a bed cover help with air resistance?

4. Didn't realize till after I bought my Nittos that they are 10ply sidewalls, are they affecting my MPGs?

I realize I'm only looking for a 1-2 mpg gain, but when my fuel costs were over 6000$ last year, I'm looking for ways to improve it without selling my truck.

My lady is blaming all the extra "stuff" I had to get for the truck on the MPG loss, I'm looking for some clarity or an opinion, thats all.

-hdub

razzle

How many miles are on your truck? have you changed your plugs? I get between 14-15 mpg

Jesslig

You're getting "normal" gas mileage in my opinion. I have a 04 4x4 and combined freeway and city I'm getting 13ish. I have a 2" level with 33" tires



I have an app called mileage keeper and it gives the overall average of fuel mileage and mine is 13.6 as of now.

GreatWh1te

Mine has 105k, plugs and packs were replaced at 85k, just had throttle body cleaned per recommendation of the dealer, I feel like when I bought it at 79k I was getting substantially better mpg.

Not to mention mine sounds like a diesel at 1.5k rpm

Flash!

What size tires do you actually have? You mention 285/75/17 but I think Lariat stock wheels are 18s and Nitto doesn't make a 285/75/18 Terra. Bigger tires are the quickest way to make your gas mileage suck, but if your tires are different than stock and you haven't recalibrated your speedometer (most people use programmers for that) then your gas mileage calculations aren't accurate anyway.

GreatWh1te

Well I know that I have one size bigger tire, relatively close to a 31 or 33inches. I'm really bad at remembering what the size was, I can tell you its larger than stock, and that the ford dealership ordered them and put them on, so they calibrated the speedometer correctly for me.

From what I've read over the past half hour, the bed cover isn't doing me much good. It was a cheap canvas like cover that came with the truck when I bought it.

I'm not really thinking the exhaust is helping, since I don't have tunes for the truck, and probably wont be buying custom tunes if I do.

MatthewR

I have an 08 with close to the same aftermarket products you have and my mileage is the same as yours. I think it just part of being a truck owner. I got a lot better mileage before I did the leveling kit.

'05 F-150

i know tires are the biggest MPG killer 10 plys are not helping even so i feel you getting bad MPG seems low, my '05 5.4 3.73 16 city and 20 to 21 HWY, mods: PHP Tuner, CAI, throttle body spacer, all normal mods, i keep my front tires at 10psi over max pressure back 5 psi over max pressure, have done new plugs, try running a cleaner thru it Seafom

GreatWh1te

Tires I have 285/65/18

Stock is 275/65/18

I may just bite the bullet and get the PHP tuner

strawsb

I have a 2005 fx4 with 5.4 of course and get 13 city and 20 highway! 76k on the truck! Mods are K&N CAI, bully dog tuner, Custom computer remap by yours truly (I am a ford tech at a dealer), comp cams, and exhaust! But I am also making 450hp or more! Also tires I am running are 275/70/18 and I have brush guard as well so it's not that! Most people need to see if there is a update for your PCM on 04-07 f150 trucks! Makes a big difference