Originally Posted by Bigbucks243

I wouldn't think a level would kill your mpg, I mean most people can put lifts on there trucks and keep close to same mpg (with same size tires), tires in the other hand is what kills it.

Originally Posted by hdub00

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

Originally Posted by chocolateskwlbuss

How many miles do you have? Have you ever had the throttle body cleaned out? My rpms are bouncing around (680-410 during idle) and I talked to my mechanic, our trucks (04-08 5.4L 3V) need the throttle bodies cleaned once and while, something about a sensor that gets grimy and throws a code equally bad gas mileage. This guy was a ford cert. mechanic for like 20 years and a dodge and Mercedes (diesel) mech for 6

Originally Posted by hdub00

I made a post somewhere that I did get it cleaned out a month ago. Idle was low so I got it cleaned and a new battery

Originally Posted by chocolateskwlbuss

I'm outa guesses then. I would say tires. I've got 33" Terra grapplers on my truck now but I alternate in between a set of trail graps as well. They both milk my MPGs, the trails do the most though