Average with town/highway driving is about 15ish....

Best Ive ever gotten was 20.7 or 21.7...cant remember for sure. Babying it, cruise set on 65, all highway.

06 Reg Cab Short Box FX4 w/ 3.73s....

 

Yah, you're probably driving slow as ***** too.

 

Jaderbutt, There's nothing wrong with your truck's MPG and most folks believe their MPG numbers are right so remain calm... It would help you feel better if you only looked at trucks with the exact same year, rear-end setup (3.55 is better MPG, 3.73 is worse MPG), tire size and 4x4 setup though. Also, ensure they're measuring mileage manually based upon actual gallons put into the tank instead of the trip computer (for Lariats) which inflates the MPG figures just under 1MPG in my experience.

Just as an example, my '02 screw Lariat with 5.4L, stock BFG A/T tires, 2WD and a hard tonneau cover got 13.5 city/15 hwy. My '08 screw Lariat w/5.4L, stock BFG A/T tires, 2WD and soft tonneau gets 16+ city and 19+ hwy (while the '08 trip computer says 17.2 and 20.5 generally). I drive real easy. The new spark plug design in 04-08 models and the 3.55 rear end are the key differences in my '08's MPG numbers I believe.

Tires in the same size of varying 'softness' (ie, higher roll resistance) can make a 2+MPG difference alone. For example, I lost 2mpg going to Goodyear SilentArmors over a hard tire on an SUV, but the softer tire had a better ride and traction as the trade-off. Going to LARGER tires is an even bigger MPG difference and leads to the desire to re-gear the rear-end and/or buy tuners so you pay both now and later for looking cool of course. (I don't plan on lifting the truck or anything, so I'm happy shaving $50-$75 off my gas bill each month with my '08 road truck setup).

Myth busters scientifically tested whether tonneaus make a difference in MPG. They didn't. Use a tonneau for the utility, not the MPG IMO.

Last but not least, a lowered truck might be more 'slippery' with less wind resistance and may get better MPG, but usually folks put on performance toys like tuners, blowers, etc. on lowered trucks which gives you oranges again! Happy number crunching from here.

 

I do better in summer with the warmer temps for some reason. On long highway trips I average about 16 to 16.5, going between 75-80 MPH and not being easy on it at all.

When it's really cold out, even on flat highways, I only get about 15.2 MPG going 75-80 (which puts my tach at barely over 2,000 RPMs.

I've got a 2004 Lariat new body style, 4x4, 5.4L, supercab.

 

I do believe the reason for better gas mileage in the summer is the warmer air is less dense, funny how you make more power on colder i.e. more dense air. oh weird science...

 

Just for the record, MY trip computer in my Lariat is dead on each time I've done a comparison on a 350 mile trip. DEAD ON!

 

Yeah about 17.5 on the hwy avg and about 13 around town. Normally avg a tank at 15 or so on my '04 4x4 5.4

Not bad at all for a truck IMO

 

18-19 on the hiway, and thats keeping it around 75.

07 FX4 w/3.73s

 

Winter gas sucks = lower mpg

I get 12 city 16 highway.

 

Sorry for the late reply, I just want to thank you guys for the info and replys. I took a road trip over the weekend and found that my highway mpg is actually alot better that I had thought. My dumb*ss never considered that my "average" included mixed highway and city driving. Again, thank you and try not to be too harsh on the reply. And to update, when I get my check from Uncle Sam the MFG A/T 305/65/18 are going on (as long as the wife doesnt get the check first)

 

Interesting. What tire size and rear diff do you have?

 

I get 12.5 on the H-way

 

Yeah 70 kills the mileage. In my truck (05 FX4 supercab) 70mph is right at 2000rpm and at that speed it takes mroe to keep the truck going.

I usually keep it 65mph or a little less.. I get about 16mpg average.

THe best I ever got was 19.6mpg... I did this by keeping the truck on cruise at 55mph sometimes 60mph. Hardly any stopping and no hard accel.



So try and keep from unnecessary stopping, fast takes offs and keep the speed as close to 55mph and see what you get.