Ford 5.4L gas mileage w/ Chevron Supreme

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Sep 12, 2002
Vehicle: Ford 2003 E-250 w/ 5.4L SOHC V8 (MPFI) Miles on vehicle: about 3000 (total of 4 oil changes so far - I like to keep the engine supplied w/ fresh oil every 1k miles or so before its broken in) Oil: Chevron Supreme 5W-30 Filter: SuperTech ST2 Gas mileage on all highway driving: 18.4 Gas mileage in mostly city driving: 13 It has 3.73s with a Traction-Lok LSD. In comparison, my 2000 Ford Crown Victoria gets a max of 22 mpg on the highway (3.55s, TrueTrac LSD, 4.6L SOHC V8) I thought 5.4 SUVs and trucks got around 16 mpg TOPS on the highway?
All depends. Lots of folks routinely get 18-19 mpg on the freeway with the 5.4 in the F150. Any city driving and the mileage promptly drops off. Also have to drive a reasonable speed on the freeway to see it (and no, 80 mph isn't that speed (for fuel economy anyways!) [Big Grin] ) Overall average on the 5.4 in the F150 seems to be around 14-15 mpg.
wow I dunno what to say - either Ford did a decent job w/ the trucks or they did a crappy job with the cars! 18-21 mpg hwy for my 00 Crown Vic 16-18 mpg hwy for my 03 E-250 w/ 5.4 V8 hmmm [freaknout]
Metro if you're getting 18+mpg on the highway with only 3,000 mi on the truck you're doing real well. After 10,000+ miles on the engine you should see even better mpg. I don't think the oil has much to do with getting that mpg. I have a 2002 F-150 4.6L supercab with the 8'bed and a 200+lb fiberglass cap and at best I get 16.5 mpg on the highway. Of course "on the highway" usually means I'm in bumper to bumper traffic or I'm doing 75 mph [Big Grin] . Whimsey
I will say in general, the GM trucks are better at gas mileage, then the Fords, then Dodge. You'll find lots of Ford 5.4l owners who wish they got the freeway mileage the 5.3l engines in the GM trucks get. And yes, expect your fuel mileage to get better as it seems it takes about 10,000 miles on these mod motors to loosen them up.
But from what I hear the Ford trucks/vans get superb brakes. I think the E-250's rear rotors are just slightly larger than the stock front rotors on the Mercury Marauder [Eek!]
Don't want to make you feel bad, metro, but my '97 F150 with the 4.6 gets just as good of freeway mileage as your vic - generally between 18-22 mpg. Best ever was 23.8 mpg coming back from Colorado. My overall, nearing seven year average is now 16.9 mpg. That's on an extended cab flareside 2wd F150 with the 4.6, 4r70w tranny, and 3.08 gears in the rear end. Not exactly a monster off the line, but the 400+ mile tanks of gas are nice (like when I drive to Colorado and back - one stop for gas! - 920 miles one way.
Wow, I never knew Ford trucks got such decent mileage for their size and engine displacement! The E-250 w/ the 3.73s and 5.4 feels like a stock non-HPP Crown Vic off the line (believe it or not), which surprised me. I used to have a E-150 w/ the 4.9L I6 and 3.08s in the back - it was an absolute dog w/ no cargo. W/ cargo it was slower than a Hummer. [Frown]
One question...are you concerned about warranty issues by not using the recommended 5w20? I don't disagree with your use of 5w30, just curious. Also, the people who have posted UOA here using Motorcrfat 5w20 have gotten good wear numbers and it may increase your gas mileage. I use Castrol GTX 5w20 in my Ranger 4x4 3.0 V6 and average 22mpg with a mix of driving. That's better than the estimated highway only figures.
My friend's 2003 Z71 P/U 4x4 (I forgot engine displacement but its way up there - gas V8) sucks gas according to him, I think he said he usually gets less than 15 mpg hwy! [Frown]
metro, contact about your vic, and tell them you want a "gen 2" chip. With it you install colder plugs and 180deg. t-stat. On my thunderbird, highway mileage went from 20mpg to 25mpg. That's with doing 75-80mph. Others have seen 30mpg.
I already have one of those chips - 180F T-stat and AWSFA-12C plugs installed. Best I've seen is 22 mpg on the highway. T-birds and Stangs are different. The Vic has 3.55s in the back w/ 225/60R16 tires. I've heard of STOCK pre-98 Vics getting 30+ mpg on the highway w/ 2.73s in the back.
I have a bone stock 1995 Town Car, 4.6L 4R70W tranny, I get 18 mpg city and 23 highway. No mods at all. I run Mobil 1 5w/30, and keep tires inflated to 32 front, 35 rear. My Ford Explorer, 4.0L OHV, 5R55E tranny, gets about 16 MPG city and about 21 Highway.
Yes I forgot about them - the Town Cars did have 3.08s available to them. Regardless you have 3.08s - they really help with gas mileage. The lower (numerically) the rear end ratio, the slower your off-line acceleration but the better your gas mileage is on the highway and city. Since I have "short" tires (225/60R16s) with 3.55s, couple w/ poor aerodynamics and a lead foot - my 2000 Crown Vic hogs gas if I drive aggressively.
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