First of all I am new here, so I hope I can find what I am looking for.
I have a 1994 F-150 ext cab, 4x4, 5.8l. I was trying to find an inexpensive way to increase fuel mileage. Right now I am getting about 10.5mpg.
Also, tires are 31-10.5-15r.

 

easiest way is to change your driving habits (no hard accelerations, use cruise control, try not to let your rpm's go over 2k)...other than that you can keep your air filter clean, along with your injectors.

There is no quick, cheap fix to increase gas milage, anything that claims to significantly increase gas efficiency is probably a load of crap.

 

properly inflate tires, fuel and air filter, get rid of all the extra crap in your truck to lighten the load (golf clubs, tins of copenhagen, you get the point), light foot.....

 

Empty Budweiser cans.....

 

What about a chip or a tuner? Will theese help?
If so where can I get info on them???

 

One other thing that hasn't yet been mentioned: a simple tuneup. Change plugs, wire, rotor, rotor cap... that stuff will make a big difference if its worn...

 

'95 with a 5.8 here so I can relate. I take off the gate when I'm on the highway, some will say it doesn't help, my gas receipts and mileage logs say I get about 3 more miles to the gallon with it off than I do with it on, but that's still only about 16 mpg so nothing to cheer about.

I've seen a few chips that claim better mileage, but they seem to get it back in performance changes, I've thought about this one, but I haven't found anyone who's actually used the thing, I really don't need anymore power than I have now, but if it actually gave me a bit more juice without using more it wouldn't be a bad thing.

 

Most of your fuel mileage is probably being lost in your tires assuming that you haven't changed the gear ratio. Unless I am wrong, your truck probably came with a 235/75R15 size tire. That tire is 28.87 inches tall overall. Your tires are 31 inches tall. This forces the engine to work harder during acceleration and at speed. If you want to keep the larger tires on it, then you might consider getting a different gear ratio in both your differentials. For example, change 3.55:1 to a 3.73:1. For example, when I wanted to change the tire size on my '99 F-150 from a 235/70R16 to a 255/70R16 it was necessary for me to change my gear ratio from 3.08:1 to a 3.27:1. This helped correct my speedo for the taller tire and didn't affect driveability or mileage in my truck. Hope this is of some help.