My 05 quad cab 4WD has the 4.7 with the 45rfe auto. IF I set my crusie control at 57 I can get 19 plus. Thats mostly on state road type driving. My commute is 50 miles each way and I have about 45K on this one after a little over a year. Just today I changed over from standard Pennsoil to Mobil 1 extended range oil. Im curious to see if I get any bump. Next week I will be installing the Champion Irridium plugs.

 

05 quad cab regular V8 auto, in city driving I avg about 17 mpg(never get above 45mph around here) on the highway I get about 20, once I get over 70mph the mileage comes back down, 50mph seems to be the magic number for best fuel mileage in my truck. Being a dog of an engine helps, I never get on it because nothing happens when you floor it, that saves a ton right there.

 

Durring the breakin period the computer dumps more fuel into the engine which could account for some of your mpg being low. I don't know exactly but my 05 v6 QC changed somewhere around 5k. Just a thought not a garuntee!

P.S. Hard acceleration can severly reduce mpg expecially in bigger engines and varys with payload.

 

hey I'm back well tried a tank of super unlead and went all the way to 12 mpg and I drove it EASY I think I'm gonna take it back to the dealer after listening to you guys my truck sucks my 01 QC 4.7 got 15 to 17 city part of my last tank was on the highway and I still get ****ty gas milage aaaggghhhh oh well

 

yea somtin bout that just don't sound rite. Good luck man.

 

Well Mobil One proved to me over the last couple days its a milage boost as well as better engine protection. I can get a tad over 19 MPG but usally average around 18.5 to 19.5 if Im carefull. I got 20.25 MPG avg for about a 225 miles over 2 trips to work and a bit of around town. Im going to see if I can hit 21 by the end of the week if I dont drive around town, just the cruise to and from work for a couple days. Thats about 210 miles.
Im convinced Mobil1 is worth 1 MPG at least. Pays for the difference over the year and then some.
Next step is new plugs.

 

the HO does not REQUIRE premium gas, it only recommends it. The HO will run on 87, the computer just retards the timing so much to eliminate ping that it runs like crap under hard acceleration. Use 93, your getting the full 260 ponies.