5.4, 3.55 gears, super cab, with 75% highway, the rest moderate city driving... gryphon on level 2

i was getting 13 mpg consistently, then got a new air filter and went up to 13.5..

the first few tanks on stock tires and tune i got 15.... now a more aggressive tire and tune and i drop 2 mpg... what gives..

 

I get around 17 mpg but I commute, first oil change coming up (3000mi) plan to go SYN, maybe get another half a mile or so...? NOTE: this was on stock 18" tires, not my new 23".

 

First oil change? I hope you got one after 1,000 miles for the initial break in time.

 

This seems to be a hot topic, I am old school and we did our first at 500 miles. Now on modern engines some say 1k, some say 3k, some even 5k on first change, I even posted about this topic on BITOG and got mixed results so I am monitoring my oil and its color which is still very clean looking, it has not used much either maybe 1/3qt and it will be changed out shortly. YMMV

http://www.bobistheoilguy.com/forums...81#Post1314281

 

I'm well satisfied with the gas mileage on my 04, I average 16-18 mpg on my daily 100 mile commute. And that's on a leveled 4x4 Screw with 35" tires.

 

Not bad. Im hoping to get atleast 15 mpg. I know its a heavy 4x4 truck and not an economy car.

 

I get 16 in the city and 20 on the highway on average.

If I manage trips at 68 MPH, I get 21.5 MPG. But that's a lowered 4x2 on street tires. Wind and friction are your enemies.

 

When I first got mine it was stock 06 FX4. I averaged 15. Then I put exhaust and Edge on and drove it like I drove it stock (hard to do) and averaged 15. The last few fill ups I've averaged around 13.5. My right foot gained some weight lately though. That's all 90% city 10% hwy.

 

I average in the 14's typically with intake, exhaust, 93 perf dyno tune from VMP, and 4.10 gears with oem 20's.

 

Pretty much sounds like me. I am at 13.5 or so in the city now. I have gotten close to 18 on the highway.