Help my mpg is an 8 mile drag

[doubleaughtEB]

Hey ya'll 1st post about my double aught (2000) EB Expo she runs great, tows strong, 4xfun.. BUT, IM ONLY GETTING 6 TO 8 MPG it cant just be the 5 four. my old hoss 98 f 150 pulled 18 on the wide roads. Im noticing what feels like a drag tho. And sometimes turning in a parking lot it feels like 4x is engaged even though its not supposed to be. Could the bearings slow me down so much? The park brakes? It had air before and someone switched to coil springs recent but the shocks are shot, I figure thats the loud rattle i hear going over speed bumps and attribute the CK SUSP dash light to also, my scanner does not read any codes sooooo hmm.
Cant do? My normal replace em as I pull em tune up with the hollow daze lurking but i will pull the two hard plugs see what I see, saw from you gentlemen here that the Co2 sensors can do bad things but like i said no cel no codes. If anything there is a grumblegurgle while idleing on occasion. And ya know? It doesnt get very warm as far as the heater inside goes my cold blooded lover says she need a blanky when we take this beast for coffee and muddin. No sir, no anti frz smells, no sir no gasoline smells, have noticed the oil light flash twice but a half quart of oil aint the same as 6.3 mpg. Can any body heah direct me to a happier ending? We Really like the 250k mile green and gold cargo hauler and wish we could Do a newer decade or two model because well, Damn those things are saweeet cept they cost more than gas.... Fo now. Hangin tight in the soggy PNW wi

 

[jr1under]

That was fun to read, sounds like some of my friends and kin except more lucid. You preempted one of my best skills, an ability to belabor the obvious(do you smell gas?) but I will offer that my 4x2 Exp and 4x4 F150 get about double that mileage.

 

[lonestarjeff]

Jack up the rear and spin the tires by hand, then do the front, simple way to see if the brakes or bearings are dragging. Generally, either of those issues will cause shuddering and noise at highway speed, but it never hurts to see what they feel like.

Transfer case engaged full time would be another big drag on fuel mileage.

Jeff

 

[EngineerMike]

Mine was stuck in 4Lo but no indicator, that was easy to diagnose on the freeway, req'd chane out of the xfer-case gear change motor.
@ 167k I changed spark plugs with a nice boost in mileage (12 or less to 16-17) & utter smoothing out of misses at idle (probably original plugs way overdue)
Bad ignition can be caused by plugs, boots, coils. The gas has to be going somewhere, it isn't getting transported to outer space (that's in the Gen4 rigs, the Gen1 didn't have that technology)

 

[Johnathan M]

I agree with spinning your wheels by hand, but would add to push on the brake pedal, then get out and spin them. I had an issue on my 05' where the brakes would apply but not release right away. Ended up being the rubber hoses (both fronts) were bad and acting like a check valve. They would let fluid flow to the caliper, but were very slow to let it flow back to the brake reservoir. So the brakes would be grabbing somewhat after every time I pushed on the brake pedal. That can definitely hurt fuel mileage.

 

[JamaicaJoe]

My 2001 got 17 MPG on a round trip mixed highway/city last week. The 2013 I bought got 17.8 MPG on the same route one way.

If you are getting 8 MPG on the highway and no malf indicator or codes, I would suggest that one or more of your brakes are dragging. Most likely because the rubber hoses to the calipers are clogged up. You will notice heat and brake smell and eventually a wheel bearing seal will open up and oil will come from the axle and burn.

 

[doubleaughtEB]

Thank you everyone who replied to my winded post. I will check brakes bearings and dragging brakes asap. But you know asap comes and goes.( It's only car at present). Think I'll get to tire shop to rotate and get a look at the pigs feet. Still love it tho. Had an offer twice what I paid for it. Sellsellsell.. shhhh.

 

[MesaGuy]

5.4's are thirsty. Also, if you had the original tow package, then you may have the the low gear ratio back end differential, which costs quite a bit of gas (but gives you more torque). (Most F150's have the 3.73 gear non-LSD. Most 4x2 Expy have the 3.73 non-LSD.) But a 4x4 with tow has 3.3 usually.

Also, the sound you described of "being in 4x4" mode in parking lot in hard turn, sounds much more like the rear Limited Slip differential clutch pack not performing properly anymore. This causes a similar tire scrub behavior that you get in a 4x4 mode (but usually not as bad). But when it gets very bad, its almost as bad as actually being in 4x4 mode. (You should change the rear diff fluid (and probably the front diff fluid also), and put in 2 tubes of the Motorcraft XL3 limited slip differential fluid friction modifier fluid in the rear, and 1 tube in the front.)

'99's, and some 2000's had the transfer case in full time operation. (Always drove the front drive shaft to the front differential). Those have only the 3 speed 4x4 switch. (AWD, 4Hi, 4Lo). '97, '98, 2001, 2002 had the 4 position 4x4 switch (2H, AWD, 4H, 4L). In 2H, the front drive shaft was not driven. (And that saves some gas also.) Not sure where in the 2000 model year they switched back. (But you can tell on yours just by the 4x4 switch. 3 switch position is full time AWD, 4H, 4L), and 4 switch is (2WD, AWD, 4H, 4L).

Also, I'd run several 32-ounce (or equivalent smaller) Chevron Techron through the gas. If its a new-to-you purchase of a used in this age, I'd run TWO 32-once per tank (add one at 1/2 full, then a 2nd at full) drive that through, and do it two more times. (That's a lot of Techron, so pricey, probably $100's worth). But that will clean up the injectors and any problem pre-ignition deposits in the vavles and head.

Those things might buy you about 2MPG. The 4.6 is not as thirsty. And the 5.4 has a wide range of observed MPG. I tend to see about 8-10MPG city, and 12-15 Hwy depending on how fast I drive. (At 65, even pedal, I get 14.7) At 75-85 (I get 12) on the highway.

If the torque converter is not getting proper lockup (Overdrive), that will cost you as well, but that would normally generate a flashing light on the transmission stick wand (on the overdrive light.)

 

[jr1under]

Maybe not apples to apples but my 2005 F150 5.4 4x4(3.55 LSD) gets around 15 mpg city.

While zeroing out the maintenance on both my Fords a few months ago, I drained and cleaned the rear diffs. The F150's was less than half full, nasty and judging by the patina of the bolts and cover, had never been changed. There were no symptoms but it was probably just a matter of time before something went out of skew on the treadle.

 

[whtbronco]

I recently experienced an overnight significant increase in drag and a 20% drop in fuel economy. The front wheel bearing hubs on my 2004 were the cause. I suppose the heat generated by bedding new brakes was simply the last straw for the hubs at 286k miles. Everything was fine while bedding the brakes and on my way home, it was immediately apparent pulling out of my driveway the next morning I had an issue. It took me several weeks to isolate the issue. They still had no play, but did not rotate well with weight on them. Once off the truck they spun very freely, kinda strange to me.

My suggestion is that your fuel economy is so low it may be multiple factors.