Just saw your problem, I've had a bunch of these 4.9s, and mileage isn't one of their strong suits, I've had 1 freak that got 24 mpg on the road (81 F100, 4spd, 2.73, 1 Bbl. carb) but usually get 12-18 averages, depending on trucks duty, gear, etc.Your truck should definitely be on the high end of that scale.A2.73 with a manual overdrive is going to be seeing alot of wide open throttle at low rpm's, and any excess drag is going to really kill it. I would check your brakes carefully for drag, pay attention to how much throttle it takes in 5th gear and how it sounds when youre there. A clean air filter, fresh plugs, and new top quality wires(installed WITH dielectric grease) can make a big difference on a truck this age. In fact one of my trucks is a 92 F150 4x4, 4.9L, M5OD, 3.55 rear, with 96,000 miles was down around 13mpg, the above tuneup brought it back to around 16mpg, mainly I think due to the wires. It wasn't missing or rough, and it is always maintained, but old wires just don't do the job. A final (and tedious) step is to rent an analyzer that allows you to view your operating parameters as you drive. Watch your fuel flow to each side of the circuit as you drive( have afriend do this, as there is a lot to write down) at different speeds in each gear. Do the same with spark advance,air flow,o2 sensor, and note whether in open or closed control loop. I won't get into all the variables or I'll be writing a book, but with this information and a little head scratching you can usually see some thing out of whack, even when you have no codes in your vehicle computer. Just remember electronic controls arent magic,they just read and react to what they see, and sometimes they don't see what is really there. Good Luck, Sun's out, gotta go...

 

I own a 96 f150 reg cab short box with 300 six and 5spd OD. I get about 17mpg in summer and 15 in winter. You might try to put a vacuum gauge on it to find out if you are lugging the engine too much. WOT at low rpm will not be good for mileage. My 67 with a 76 300 in it got about the same 15 - 17. Most guys I know get about the same.

 

>I own a 96 f150 reg
>cab short box with 300
>six and 5spd OD.
>I get about 17mpg in
>summer and 15 in winter.
> You might try to
>put a vacuum gauge on
>it to find out if
>you are lugging the engine
>too much. WOT at low
>rpm will not be good
>for mileage. My 67
>with a 76 300 in
>it got about the same
>15 - 17. Most
>guys I know get about
>the same.


this may be a stupid ? but here it goes what is WOT?

 

WOT-Wide Open Throttle

 

WOT = Wide Open Throttle.

1988 F-150, SWB, 5.0 EFI (formerly 4.9 EFI), M5OD 5 speed, 3.08 gears, Summit shorty truck headers, Custom built Flowmaster exhaust system. Force 4 LP6000 lightbar, Federal signal PA-300 100 watt siren, Icom IC-V100 50 watt mobile radio.
=======================================
1965 F-100 (just purchased 1/18/01), SWB, 390, C-6 auto. Dual exhaust, Not much else to do to it.

Can see both below.

[link:www.geocities.com/hotrodford_88/|Hotrodford_88's Webpage]

 

[font size="1" color="#FF0000"]LAST EDITED ON 03-Mar-01 AT 06:46 AM (EST)[/font][p]Boaters know that WOT = wide-open-throttle, and I'm a boater. But here's my "stupid question:" What are "side-gapped plugs?" I'm familiar w/ the practice of "indexing" plugs, i.e., using various combinations of plug gaskets to arrange to have the plug reach max torque precisely where the side electrode is not blocking the flame-front path b/w the center electrode and the combustion chamber. Is this the same as side-gapped?

BTW, indexing sounds like too much work. Has anybody done it? Did it make a difference? I could see doing it on my Honda ATV, as there's only one plug, so more critical and less work. Anybody?

Oh yeah, mpg. I have three sixes, and the best I've ever seen is 19mpg, only once. They've all got good vacuum, I know the compression on one is 180 - 190+ and I keep 'em tuned. The '81 gets about 16 - 17 (2.42:1 rear) and the '88 gets 15 - 16 mpg (3.55 rear). I short shift at 2,500 mostly--what RPM are you shifting at typically?

 

My '82 f150 300 with 4-speed no OD and 3.08 (i think) gets between 15-20 mpg on the highway, it degrades in winter, but a part of that could be the few hundred pounds of sand i put in the back in winter.

As for shifting, i usually shift around 2500 for normal driving, around 3500 when i need acceleration.

-Der Meister-

 

what are you complaining about my one ton had a 3oo and it got 10 miles per gallon its got a 240 in it now and i get 8

 

...was what i got on a recent weekend roadtrip. Avg speed to get 15mpg was 65 to 70, on the way home i cranked it up to around 75 mph and the fule consumption skyrocketed (note: there were some fairly strong head and cross winds that particular day which no doubt also contributed to the bad mpg #'s)

Avg over the past few months since i bought the truck has probably been around 13 mpg with a good mix of city/hwy driving. With gas prices climbing now i'm looking around for anything that might help improve my mileage numbers. (putting $75+ worth of gas into the fuel tanks is NOT something i want to have to do any more often than absolutely necessary...)


wolf189
************************************************** ***********************
'93 F150 4x4 Regular Cab, Long Bed - 4.9L I6 w/5spd Manual
no mods... yet...

 

My 6-300 gets ~14 MPG. It's a '79 in a F100 body with at least 180K miles. Drives great!

 

oh yeah, it's a AT with a C4 (no OD).

 

[font size="1" color="#FF0000"]LAST EDITED ON 28-Apr-01 AT 12:32 PM (EST)[/font][p]i have a '94 2WD F-150 5 speed, with the short wheel base. i dont konw what the final drive ratio is but its never been changed from stock. i get about 15 or 16 on the highway and about 12-14 city.

 

I have a 95 4.9 liter with 5 speed. My last highway trip I averaged 24 miles per gallon. I thought this was a normal reading? The only thing I have is a canopy on the box, which might help a lot. Never drove the truck without the canopy.

 

 

I'm not sure what the OD gearing is on the 5-speed, but I know that my truck would constantly kick out of OD on the smallest inclines or headwind. This was with 3.08 gears and 235/75R15 tires, so you might be having the engine really bogged down with the 2.73 gears running in OD. My tach showed 1800 rpm @ 70mph, but I think the engine would be happier and run more efficiently at around 2000rpm.

Consequently, I'm still running the 3.08's with my new 35 inch tires. I can't use my overdrive, but running in 3rd gear (1:1 ratio) puts me at 1700rpm @ 65mph, so it's pretty close to what I had before. The only real difference I've seen in gas milage is wen doing alot of in town driving. On the highway, I'm still getting about 16mpg, but it drops to about 10-12mpg in town.


TrailDawg
https://www.ford-trucks.com/dcforum/User_files/3aaa4bac6f539876.jpg
1993 F150 2WD
6" Lift w/35's
And STILL waiting to get my 4.30 gears installed!!!!
http://www.geocities.com/ProjectTrailDawg