I just bought a 92 F150 4x4, 300 5-speed manual. I am getting anywhere from 12 - 15 MPG. I do have a K&N Filter Kit on the truck. My questions are:

1. What should I be averaging for gas mileage?

2. What can I do to improve the mileage?

I put on alot of miles so to spend $100 or so to go up 2-3 mpg is worth it for me.

3. Also, Is there an operating range where the truck gets the best mileage, 1600Rpm, 1800Rpm, 2200Rpm?

Looking for anything that might help this thing get above 15 on a regular basis. I don't want to drive the wifes Chebby.

 

1700-1900 rpm for a carb'ed engine is where the power band is, so that is where it makes the most power. Also, any performance mods that you make, like a larger exhaust, or to go all-out with a ported head, higher compression, Offey intake, dual exhaust manifolds, and a TBI kit, will increase mileage, if you can keep your foot out of it. That is why a larger engine can sometimes get better mileage than a small one.

Jared

 

I am having the same problem. I have done all the tune up stuff but it hasn't help. A friend has the exact same truck as mine, only his is an automatic and mine is 5-speed, and he gets 19-20 on the highway and 15-17 around town. The best I have ever gotten is just under 15. Oh, his truck also has just shy of 200K miles and mine only has 89K. Both trucks are 2WD and 92 models. I am starting to get frustrated. I knew I should have bought a Toyota.

 

That is what I have been getting. Just had a glasspack put on today, I'll see if it helps any.
Lars

 

I get 16mpg EFI 4.9L M5OD with original cat, no mufflers, 215,000 miles.

 

Been driving F100's and F150's for almost 30 years...rarely has my MPG been consistently better than 17-18 mpg. Course my newest vehicle is a 90 F150 4.9L that gets 17 regularly in town and 18-19 down the road with the tailgate down.
Fords need hot spark, unrestricted fuel flow and open, flowing exhaust to maximize mpg and engine performance.
I run a stock coil, performance dist. cap and wires and autolite side-gapped plugs with no exhaust or air intake mods on my 90 F150.
If you want better mileage, make sure the fuel system is okay then consider a hotter coil, cap, wires and plugs. Then make sure it can breathe by checking/opening up the air intake as much as you can (FIPK, etc.). Then open up the exhaust so it can flow, and most importantly don't screw with your O2 sensor system.
If you can't get at least 15 mpg out of your Ford consistently, start looking to trade...there's plenty out there that make this or better every day.

 

My Bronco 83, FS 4.9 4 speed 3.55's gets a solid 21 MPG city and at least 28 on the highway. No special mod's either except the cat is removed and the air pump belt is gone. Never gotten worse then 18MPG city driven very hard, somthing is wrong if your injected I6 is getting less then 17 city which is what was on the sticker for estimated MPG when the truck was new. Start with a good tune up, change the o2 sensor (both) or a neat trick is to install a heated 02 sensors that will lean the engine out sooner, alot of fuel is wasted while the engine warms up.

 

You guys shouldn't complain i only get about 10 or 11.... Whiners.

 

maybe you should invest in a bed cover.

not sure how much of a gain it'll give you though.

 

There are people who don't agree with me on this, so take it for what its worth. I read somewhere that low RPM's and wide throttle openings (a.k.a. lugging) are condusive to good gas milage. Folks told me that I was going to harm the engine because of insufficient oil pressure at low revs. I figure the 240/300 is one motor that will stand lugging because of the amount of bearing space. Lugging allows higher volumetric efficiency with lower parisitic drag. It's not just a matter of staying out of the throttle, but staying out of the revs as well. I'm not saying to give it full throttle at 200rpm, just make an effort not to use any more revs than you need to. You very well may find that your driving becomes smoother as you do this because you get used to having less throttle response. Dont be afraid to periodically "clear it out" either so things dont get choked up. I averaged about 16mpg in rural driving with a carb. I did this for about 4 years with no known adverse effects on the motor.(the truck has over 380k miles on it now!!!)

 

>There are people who don't agree with me on this, so take it
>for what its worth. I read somewhere that low RPM's and
>wide throttle openings (a.k.a. lugging) are condusive to
>good gas milage. Folks told me that I was going to harm the
>engine because of insufficient oil pressure at low revs. I
>figure the 240/300 is one motor that will stand lugging
>because of the amount of bearing space. Lugging allows
>higher volumetric efficiency with lower parisitic drag. It's
>not just a matter of staying out of the throttle, but
>staying out of the revs as well. I'm not saying to give it
>full throttle at 200rpm, just make an effort not to use any
>more revs than you need to. You very well may find that
>your driving becomes smoother as you do this because you get
>used to having less throttle response. Dont be afraid to
>periodically "clear it out" either so things dont get choked
>up. I averaged about 16mpg in rural driving with a carb. I
>did this for about 4 years with no known adverse effects on
>the motor.(the truck has over 380k miles on it now!!!)



Yes thats part of the equation but not quite true. The higher vaccum you run at the better fuel atomozation= better light cruising (LC) economy, vacuum guages are nifty tools. The throttle blade should be as closed as much possible to raise vacuum, this will pull the air down quicker and more steady to mix with the fuel raising the V.E with a leaner proper (LC) mixture. Seems **** backward I know but all the good carb books go into detail about it. With the throttle blade open too far it will pull as much air but will not have the same vacuum signal and will dump fuel creating a stronger fuel mixture dropping V.E quite a bit.

 

For street driving i've gotten the same economy with the WOT/low rpms as medium throttle/medium rpms. I even tried almost-WOT/low rpm (when you go WOT on an EFI motor you go open loop) and that didn't seem to change much.
My '81 F100 got 20-22mpg on purely street driving (rarely drove on the highway at that point), but that was carb and a whole lot lighter (shortbed flareside, swisscheese framerails, etc)... And I drove like an *** with my foot in it everywhere.


-=Whittey=-

 

 

I got a 92 f150 4.9 and get about 10 or so mpg. Has duals with turbos. Seems like it got worse after I put the exhaust on. Guess I might have to put the glasspacks back on.