My F-250 fuel filter froze up last week on a -19* day. I got stuck driving my dad's F-150. Last Feb I drove his truck and was not impressed then either!
Last Feb I noticed that he got very poor fuel mileage (11 mpg). I also noticed that the temp gauge never came off of "cold". After replacing the sender unit I changed the thermostat and got the gauge to come up to the cold side of the operating temp range. Fuel mileage went up to 13 mpg.
Last week I found the truck to be low on power and still getting 13 mpg. I changed the plugs/cap rotor... for him and haven't figured out fuel mileage yet but did notice that it is still "gutless". My wife pulled my 250 (after I changed the fuel filter) with the 150, in an effort to bump start my 250. I would rather bump start it than crank on the starter in order to get it primed. She said that when I let out the clutch in the 250 she had to "floor" the 150 in order to keep moving.

What can be done to my dad's truck to get fuel mileage up and power up. He doesn't need a hot rod just something that runs efficiently.
I am a diesel guy so changing his spark plugs brought back a lot of horrible memories.

Specs:
'95 F-150
4x4
auto
300 6cyl
162K miles
standard cab

I am thinking 20 mpg should be obtainable - is it??
I don't have a way of measuring torque - but I know it when I feel it.

I get 16mpg with my 7.3 5 spd and 4.10 gears. I get 20 mpg with my 7.3 5spd and 3.55 gears. Is it the auto that is killing his fuel mileage??

 

It could be a lot of things. What's the timing set at? Maybe the timing gears jumped a tooth? Busted valve or two? Have you checked the compression? What gears are in it? Some trucks came with "highway" gears that deliver great mileage but little power. Doesn't sound like you have either though.

 

Wait until you have to change the injectors on the diesel, then you will have something to compare the experience to.
A 300 CI six ford is not know for power put it is reliable.
13 around town is not bad for a 4x4 with the 300 CI engine.
You could possibly gain something by scanning the computer to verify all is well.
Man I know has a 93 F150 2WD since new he always drives like going to a funeral 14 or 15 is it. Almost 300,000 miles on the all origional drive train.
I have never measured 12 MPG with our F350 crewcab FI 460 SRW 2WD C6 but it aint short on power!! Crosses the scale at 5750# empty.
We use it to move a 6000# tractor on a 2000# trailer, it is up to the job.

 

you will lose some mpg due to the auto tranny. we need to know what tires are on the truck and what gearing it has. should be a tag on either the front or rear diff. the efi system will use more fuel when the engine is cold, so if you can get it up to proper temp faster that will help a bunch. I hope you put a 195* stat in there minimum. you could probably bump up to a 205* stat if your in that cold of a climate and then swap back the other tstat in the summer.

 

I forget what thermostat I put in - too long ago.
I'll check on the gearing. He is running 9.5/29/15 tires.
We don't have any cities out here, 98% of the driving is at 55-65mph with a S.S. or light every 30 miles or so.
It idles and runs smooth so I don't think there is a valvetrain issue. I'll check the timing (when I can find a light to borrow - diesel guy here).
My ex-brother-in-law had a P/U like this except is was a 4 speed and a mid '80's model. Pulled great and 18-20 mpg. I realize the fuel is blended different nowadays, this contributes to poorer fuel mileage.
Sure miss those carberator and pre-ethanol fuel days

With a 6.9 and 2 7.3's I'm sure I will get the pleasure of doing injectors someday.<!-- e --><!-- e -->

 

We run a 440 ci Carbed BB Chrysler motor, streetable HP car, in a 73 Dart it requires high octane fuel, so I still have an Edlbrock to work with.
I was at a car show, some kid wanted to know what the shiny thing on top of the engine was for [the carb]. The rear end and brakes are FORD!
We run an International 464 tractor with a D179 all mechanical diesel; 780# and 179 CI, not even a glow plug. No electrics required to run; just fuel and air.
We run a 3-71 Detroit Diesel power AC crawler; another all mechanical diesel 212 CI 1700#; Nothing like the sound of this one.
We run a FI 460 F350; big low performance high cube car engine. Smooth as glass and starts in any weather; a no issue drivetrain.
A Nissan mini truck with an FI 2.4 ltr; daily driver 229,000 miles and still haulin the groceries.
The Nissan and the Detroit Diesel are the only ones I have NOT had to do serious engine work on.
You can see lots of time can be consumed keeping this stuff together and some of it goes back to 1955 (the Detroit)
Over the years I have discovered I had rather wrench than drive.
Merry Christmas!

 

the Tstat is extremely important factor with EFI. it might be worth your time or his to pull that and put in a 205* tstat.

 

The 300's are slow and hard on fuel if you try to drive it fast, a bit better economy of you drive it like a total grandpa.

Stick with your IDI's, after buying and driving my 300 for a few months I cant stand it anymore and will be swapping the body on to my old rusted out 83 f350 6.9 Also the injectors are easy to change without turbo stuff in the way, just make sure you pick up a return line kit when you do it. I miss how cheap parts are for the old diesels.

Scott

 

I'll pull and replace the T-stat with a 205*

I love the old mechanical diesels!!
I have a '61 Cat, '66 Case, '69 Austin-Western w/ 4-71 Detroit, '85 Case and am always shopping for an excavator! Hopefully a Cat 225.
Things aren't simple anymore though. I run pre PS 6.9 and 7.3's, along with and '80 VW diesel and '82 Isuzu diesel.