What are you guys getting for gas mileage out of your 5.4's. I am getting between 12 and 14 on the highway without hard driving.

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97 F-150 5.4L 4wd. Tow pack, K&N FIPK, Carr steps, had a bug deflector (hail took care of that) Enough electronics to make Luke Skywalker feel at home

 

12-15.5 mpg. That is from 70% city and the rest from highway. Most of the time I am doing 12-13.

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My Ride: 1998 F150 4x4 Lariat Supercab Flareside 5.4L in Oxford White/gold, ORP, Tow Package, 3.55 Gears.

Modifications: K&N FIPK, Stepshield door sill protectors, Performance Accesories 3" body lift, Lift Lips, Gabriel Gas Ryder LT VST Shocks and Daystar front anti-sway bar polyurethane bushings.

Photos at: http://www.communicomgroup.com/jmtruck

 

I have always been 14-16, 60% city, very heavy foot, 85 octane. This is also with AC on in the summer. Usually 11-13 towing 2800 lb boat. But, mine is a leaker and a slapper, I hope when I get my new engine I see similar numbers....I would be disappointed with anything less.

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firstimeFord
99 SC 4x4 5.4 3.73LS

 

I've heard some of the talk about leaks and piston slap. What is the scoop on this?

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97 F-150 5.4L 4wd. Tow pack, K&N FIPK, Carr steps, had a bug deflector (hail took care of that) Enough electronics to make Luke Skywalker feel at home.
http://albums.photopoint.com/j/AlbumIndex?u=1017542&a=7497508

 

I've got a 4.6 and get anywhere from 11's to 14's depending on how much city driving I do. If I do about 60% highway driving I get in the 14's, but if I never get on the highway it's low 11's. But with city driving around here it's stop and go, not uncommon to sit at red lights for about 5 minutes on a 10 minute drive.

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black 97' x-cab 4x4, 5 speed 4.6, black westin nerf bars, pilot ground searchers, borla SS split rear exhaust, K&N genII, bosch +4 plugs, superchip, flexalite electric fan, v-tech oval side window covers, IAS shocks

premier 720, pioneer 6cd changer, 12 premier sub, premier componets, 2 soso amps

still to come: new spark plug wires, new rims and tires, maybe a supercharger eventually.

 

Piston slap can be heard at startup, usually when it's cooler outside, sound like a rod knocking. I believe this affects 97-99 5.4 engines (a small percentage).

The leak problem is on 99 5.4 with build dates from 9/98 - 5/99. The block surface is irregular, create a less than perfect head gasket seal. Oil leaks onto the exhaust manifolds (usually passenger side), and antifreeze can get into the oil if leak is bad enough.

Solution for both problems is engine replacement.

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firstimeFord
99 SC 4x4 5.4 3.73LS

 

Same Mileage here. Can't seem to do better than 15.5 on road trips. I only live 3 miles from work.


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Mines suckin wind pretty bad now that the weather has turn cold. I used to be getting about 14mpg(city), but now I'm only getting about 12mpg, or 400km/tank.

A close friend of mine works in a Ford dealership, and handles quite a few warranty jobs, in which he very much dislikes because of the flat rate times. Any ways, he's had quite a few 5.4's coming in for head gasket changes. He said the reason is because the head gaskets are so cheap, they tend to leak out! And is also pretty common with other motors also, not just the 5.4L's.

 

13.5 ~ 14.5 in mostly rural driving.
<A HREF="http://www.net-link.net/~n8jg/y2k/mvc-008s.jpg" TARGET=_blank> [img]//www.net-link.net/~n8jg/y2k/mvc-008s_small.jpg[/img] </A>

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Y2K™ Jim - N8JG@Hotmail.com

Toreador Red, Keyless XLT SC SB 5.4L E4x4 4wDisc/ABS, 3.73LS, Skid, HD 7700# Towing, LT-245's on Chrome, Tube-Steps, Captain's, 6CD, Tonneau, named: "Nick"

 

I almost always get in the 15's, but I do about 80% rural driving.

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2000 Silver F150 XLT 5.4L Supercab
3.55 LS, Class III Tow Package

Ravin Z-55 3" SI/S0
Line X Bedliner
Better Built Tool Box

FIPK up next

 

I've had my truck just over a month. Low of 13.8 to high of 16.0 miles. Commuter driving during the week and rural trips on the weekends. Overall average of 14.7 mpg over 2,350 miles. Gas milage hopefully will improve a bit after the engine gets its break-in.

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2001 F150 XLT SC SB SS 4x4 ORP, 5.4L, 3.55LS, 4x4 Electronic Shift, Towing Group, Rear Slider, Captain's Chairs, Deep Wedgewood Blue & Silver, Med Graphite interior, AND LT265/70R17 AT OWL Tires (no "P" tires - it's usually wet around here).

 

I have 11k miles on mine now and have
seen one winter and the last summer. Mostly non-highway and get ~11.5 winter and ~13 to 14 summer. However on two totally full to nearly empty highway trips last spring (when I had around 3K miles on it)I got exactly 17.8 going average of 65 mph with almost no stops. This was both ways on the 480 mile trip I took to the Carlisle , Pa. car show. I'll check it next April on the next trip when I should have 14 to 15K on it.

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2000 Lariat, 5.4, 3:55 L.S., 4wd, ext cab, Tow pkg, Chestnut/Gold, Century mid-hi cap, Ford short bug deflector, contoured Ford running boards and bedmat.

 

Summer: 12.3 HWY
11.3 city
Winter: 10 city
11.7 Hwy

No changes even after the mods. I guess I have a heavy foot.

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1999 F250 LD S/C XLT 4x4
5.4L, 3.73, 4R100 trans.
Flowmaster 40 "DF" series, K&N, Superchip, WMS Velocity Tube, Rancho RSX shocks, Hellwig rear swaybar, Stull billet grille, 2-PIAA Pro80XT's (120W), 2-KC Daylighters (150W), Clear Side Lens Mod w/ 9006 (55W bulbs). 265/70 R17 BFG AT KO's on 17x8 American Racing Atlas rims
Kenwood 7007 CD, Alpine 3342 Signal Processor, Alpine MRV-F353 5Ch. Amp, Pioneer TS-A6865 3-way speakers, MTX Thunderforms. CompuStar alarm/autostart. On the way: Performance Accessories 3" body lift, 33/12.5/17 ProComps, GSP grille guard and more KC's

 

My truck gets from 11 to 14 city from 15 to 18 highway with the 4.6 and my lead foot has some effect on it too.

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2000 F150 XLT Reg. cab
4.6 Triton Engine
4x2 3.55 rear end gear
sliding rear window
automatic keyless entry
white styleside short box

 

I've been avg. 12~14 mpg in a 97 w/ 4.6L
You can see my mileage chart @ F150IslandBoy Mileage

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F150IslandBoy

1997 F150 Lariat
SuperCab, Dark Toreador Red w/ Gold, Styleside, 4.6L, A/T, A/C, 3.55 Limited Slip, Class III Tow Package, Leather Captain Seats, Sliding Rear Window.
Modifications:
Airaid FIPK, Flowmaster Delta Flow 50 Series, Bugflector II, Viper 500ESP Alarm, Pendaliner Bedliner, Cobra Trapshooter 3 Radar Detector, CARR Tubular Nerf Bars, White Face Gauges, Ventshade Ventvisors & Taillight Covers, Monroe Sensa-Trac w/ Safe Trac Shocks, NFA 1400 Compact 55W=&gt;85W Halogen O.E. Lights, Durango 255/70R16, Chrome eyelet tie downs, Smoked front lic. plate cover.