I just bought this 1994 F150 4X4 Regular cab 8ft bed with only 90K original miles,302 5 speed.The truck is like new inside and out and is beautiful but is only getting 10 mpg.New tune up and passed emissions like a new engine.It originally has the E4od that was bad so I swapped it out for a 4 speed overdrive.I checked the Gear Ratio and it has 3:55s.Does the Automatic have the same Gear Ratios as the standard trucks??? It seems to run at high RPMs,ist gear I have to shift at around 10mph and 2nd around 20,pulling a hill 3rd its winding to tight and 4th is dead,I have to shift back and forth to make the hills??? What rear end Ratio would perform the best and plus get excellent milage? Possibly 3:25 ??? What vehicle would have the best rear end to rob from???

 

It would seem to me that the combo you have is just about ideal but I don`t have a F150. If you do change the axle ratio you have to change both front and rear.
I think, if it was me, I would check for trouble codes and I would also check the fuel pressure as the problem would seem more an engine running issue to me.
Hopefully other opinions will follow.

 

Other then the lack of power pulling a hill the truck seems to run good.I don't know what else to do to increase the mpg other then change the gear ratio.If I had other engine issues wouldn't they have shown up when I got the emission test done? The #s where all low like a new car.I thought about the converter being plugged but again the emission test was perfect?????

 

Ford Fuel Injection » How To Run a Self-Test Here is a link on how to check for trouble codes, might be worth doing.
The 302 is not known for massive torque and I have never driven a manual one but I would have thought it should be better than you describe.
If you go to something like 4.10 gears for more pulling power I would think the fuel milage would get worse.

 

are you sure you odometer is working correctly and that your speed you should be getting closer to 20 or better i would think but it also matters how you drive.(im sure you know this. im just reminding) for a note i dont think the 94 offered a 4 speed i could be wrong what did you pull it out of

 

you should be getting around 15 i would think. if you have an older 4 spd than your mileage would suffer, if its a 5 spd from a 90ish and newer than you would have 4 and then over drive 1... so a 5 spd total... if you have a newer 5 spd then i would guess that either ur odometer would be off or a fuel issue of some kind

 

It's a stock 302 that's choked off by the factory and way undergeared. Expect to have to shift back and forth on the hills.

Check everything out. Make sure the truck is healthy. Once you are 100% sure it's completely healthy, you may want to look into a free-er flowing exhaust system and a gear swap. Swapping to 4.10's would be ideal with the 302. Excellent power.

You should be getting closer to 15 / 18 miles per gallon, by the way.

 

I got the 5 speed ( 4 speed overdrive) out of a 1990 f150.I checked my speed o meter with the GPS and its accurate.The truck sat for 10 years with out being ran,I changed brake calipers,wheel cylinders,lines and fuel filter along with tune up and new u joints.When we put the 5speed in we had to use the transfercase out of the 90 since it was different from the automatic so I can eliminate that but could the rear ends be tight from sitting???

 

I would bet so. Lube everything up you can and check all the brakes again. Make sure nothing is hanging up.

That's a long time for a truck to sit.. A very long time.