mileage sucks

[oi8228oi]

yesterday was the first day i go to really go on a road trip and check my highway mileage. i drove 470 ish miles round trip (only heavy on the gas a couple times) to see my dad. when i got home i filled my take 30ish gallons my mpg came out to about 15.3 if i remember right. now city driving (what i do all the time around jersey)gives me 13.5-14.5 mpg. so what im asking is why did my mpg suck so horrible on the highway i was expecting at least 17mpg. what can i to to fix this....

 

[CHPMustang]

I'll take a couple swings at; lesser than regular quality fuel on this tank,fuel filter needs replacing,Air filter needs changing/cleaning,oil/filter needs changing,air in fuel,tire pressure,highway speed,ambient air temperature,etc. I could go on and on but you have the idea

Just go down the list to eliminate possible suspects

 

[fgtex]

Check out what CHP said. I have noticed on my stock '02 that when I stay over 2k rpm's, the mileage goes down noticeably. On spring break this year, when doing 80 through NM and AZ for tanks worth of fuel, I got like 12.5 mpg. No trailer, few hundred pounds of gear.

fgtex

 

[nevrnf]

1st off you have 4.11 rear, Right? What rpm were you running? What mph? Best MPG is obtained at or under 2000 rpm. On a 3.73 gear that is right around 67mph. I bet you were humming along at 75-80 mph and the tack was around 2600-2800. Not a good combo for fuel mileage.

 

[powerboatr]

stay below 2k
oh yeah thats a good one i would be doing 60 and wouldnt be in the strong power band
now way\but on our 02 with 4.10 we got 13 before the predator, and i drive 76 or better

after predator we gained up to 16 or so tooling n the highway

 

[oi8228oi]

I'll take a couple swings at; lesser than regular quality fuel on this tank,fuel filter needs replacing,Air filter needs changing/cleaning,oil/filter needs changing,air in fuel,tire pressure,highway speed,ambient air temperature,etc

running # 2 with 32 oz of diesel kleen. tank before had napa diesel conditioner. same place for fuel every time (where i see 90% of trucks go), fuel filter less then 2k on it, air filter bully dog rfi looks kinda like faded paper now but not dirty. air in fuel good possibility, tire pressure seems fine on the 4 tires i see everyday, havent check others, speed was 73 mph cruise control set, windows open (till it started pouring) and radio cranked. there was 1 or 2 incidents where i did hit about 95 ish cause of @$$holes tailgating for no reason but not many incidents. mostly flat terrain, till end of ride went up and down couple hills. had nothing in tow and nothing really in the truck.... bully dog power pup set on 120 hp, outlook monitor set to use 75% of that... well i hope that clears things up... more output????

 

[oi8228oi]

is it definet i would have 4.10... should i concider making a change to 3.73's???? for a gas perspective or would that be useless in a dually??


ps 93 degree day was great at the beach here in NJ

 

[snowman]

i have a 3.73 gear in my 350 SRW. i've pulled our race car 40' race car bumper hitch trailer through ohio at 55 mph..lovely ohio speedlimit..and got 15 mpg..not pulling the trailer i get approx. 18 - 19. all i had on it at that time was just a superchip on the tow safe setting.

 

[oi8228oi]

maybe ill have to do that and switch to 3.73's when i do my diff covers.. might as well burn all the $$$ at once

 

[nevrnf]

If the truck is a 4x4 it is not going to be cost effective to change the gears. By the time you do this it will take you like 5 years to recoup the expense with the 1-2 mpg improvement you get.
Just wait till the new ULSD diesel gets here later this year and watch your mileage drop again