4.2 mpg

[RLDSL]

A good friend of mine inhereted a roughly 2003 f150 that has a 4.2 in it with a slushbox, byt the axle code ( 19) it looks like it has a 3.55 open diff. Truck is completely bone stock and has only 29k moles on it and is in perfect condition, he inhereted it from his father in law when he passed away, and now he only drives it maybe twice a month, but due to fuel consumption, but when I heard that the thing was only getting 16 mpg on strictly highway runnning ( and I've known the driver for decades, he's pushing 60 and has a REAL steady foot) something didnt sound right

What would the *normal highway mileage be for a truck like this with a civilized driver, and what might be causing a reduction in mileage?

One hint, While we were visiting, he asked me to check out a pulsation in the brakes, and I found surface rust that had settled on his rotors causing his pedal to pulsate when braking ( which I imagine was also dragging going down the road ) I got in it and rode the brake lightly for a couple of blokes to skin the rust off and that got rid of it, but I couldnt imagine surface rust lasting on a long trip.

Thanks

 

[bigoilburner20]

I have a 01 chevy 4.3 and I roughly get 16 to 18 mpg on the highway I mean I have a full size 2wd also so most times its always better with a v8.

 

[RLDSL]

I dont know about a v8 being better. Years ago I had a ford van with a 300 straight 6 and a 3 on the tree ( non overdrive tranny) and the worst gearing on earth for fuel mileage, a 5.13 rear. The beast would pull ANYTHING, and shockingly it got around 23+ mpg running around empty on the highway( although with that rear end, about 60 mph was wound up tighter than a drum) but it did get great mileage
THis new injected 4.2 is a much more powerful engine and should be more efficient I cant see why it shouldnt be able to do at least as good

 

[kc0stp]

Sounds about right, our 2002 Ranger got 16-18 with a V6, traded it in on the 2010 F150 and are averaging 18 mixed driving (got 22 on a road trip to FL)

 

[bigoilburner20]

i guess they dont make truck or vans like they use too 5 13 gears holy crap i thought lower gearing was better

 

[DesertBen44]

Mpg sounds about right for that motor. Trucks that era really only gained power and emissions, significant gains in reliability and mpg were not happening. My opinion obviously. I agree with bigil, my experience owning a fullsize truck the larger motor wll get the same or better mpg as the v6 or smaller motor option. At least this proved true with every dodge 5.2 vs 5.9 (gas) that I have know of

 

[RLDSL]

Mpg sounds about right for that motor. Trucks that era really only gained power and emissions, significant gains in reliability and mpg were not happening. My opinion obviously. I agree with bigil, my experience owning a fullsize truck the larger motor wll get the same or better mpg as the v6 or smaller motor option. At least this proved true with every dodge 5.2 vs 5.9 (gas) that I have know of

I guess ths shouldnt shock me. Back when I had that van, I had a buddy who went and bought a toyota mini truck, and that little pos only got about 15mpg and was uncomfortable as all get out, and I never could figure that one out when my big ol ford van was getting 23+

I guess with the old larger long stroke engines and a carb you could have a lot of input for the fuel mleage with your foot, but with the newer smaller engines with electronic controls that always feed a 14:1 ratio no mater what you do and are setup to pull, they are going to consume a pretty much pre set amount of fuel, unless you go into the computer somehow .