blade z51

I bought a beautiful '94 F150 XL truck. It looks immaculate and everything works in it. However, my gas mileage is quite poor. I get just a bit over 13 mpg in combined highway and city driving. I drive very carefully and try not to use my brakes, accelerate gently, coast when possible, etc.
I also tried keeping the A/C off and generally keep my speeds in the lower ranges (55~60 mph max).
I realize that this puppy's weight is probably near 6000 lbs, but I really think that the fuel consumption is too high. Does anybody know what if anything I might do such as troubleshooting or checking to make sure I'm getting the best mileage possible? Could it need a tune up or some maintenance I have not done? I would appreciate any help or advise. I love driving my truck, but it can get quite expensive to drive

ymeski56

More like 4400-4600 lbs. Curb weight.
Do error code scans & deal w/ any active codes. http://www.handsontools.com/Equus-In...ol_p_5574.html
Seafoam treat the engine https://www.f150forum.com/f33/how-se...-1991-a-31505/
Transtune treat the transmission
Switch to Synthetic fluids
K&N drop in air filter only if not a MAF engine
Do this Ingition System upgrade Mod (includes stretching plug gap & further advance of base timing afterwards) http://fullsizebronco.com/forum/show...ht=timing+bump
P/u a Haynes repair manual
Consider replaceing O2 sensor(s) ahead of the Cat at 60K miles. No later than 100K miles. If you have any O2's mounted after the Cat, They're not really critical to fuel trim. !00K's a good time.
Stick w/ 87 octane
Stock tires properly inflated
Don't lift
Lucas Injector cleaner periodically
Conservative driving style.

My 87'302 gets 20mpg @ 65mph (your results may vary/ depending on stuff like your cylinder compression, tire size, added lift, gear mods, How fat your girlfriend is, ect...)

sporkme

Which engine?

For dual gas tank models, cross-filling might be screwing your numbers up.

ymeski56

All engines w/ exception of the Ignition system upgrade.
For that, any gas engines w/ a distributor. 6's & 8's.

blade z51

Thanks for the tips. I have the 5.0 engine and as far as I know, they serviced it before I bought it. I don't know exactly what they mean by "servicing". Perhaps all they did was change the oil and transmission fluid. I believe they changed to synth fluids too (I'll check with the mechanic who is a friend of mine).
I do use 87 octane gas and I think the wheels and tires are the standard size. I haven't had a fat GF in many years and my wife is very petite (I aint too heavy either). Your mileage numbers are excellent! I get only a few more mpg than you from my 'Vette on highway driving...

hotrod351

i have a 90 with the 4.9 and get 15 mpg, that what fords web site said my truck should get so with a 302 i would think youd get worse than my 15 mpg. in other words 13 mpg for that is right. i cant find the site or id attach it.

blade z51

Hhhmmm... I was wondering what I could expect from this truck. It seems that other people get almost double the fuel economy that I am getting. My truck runs really well. I cannot detect any misfire, hesitation, loss of power or anything like that. Of course, I have no way to know yet if there is something wrong that I cannot detect from just driving it.. I'll see if I can take a look at the air cleaner and later at the timing and see if any codes are reported.
Otherwise I might have to live with the 13 mpg.....

ymeski56

That's stock. Stock Coil, plug gap, wires, cap & rotor, wires, base timing advance, Cat's, exhaust, air filter, Thermostat, Fluids & lubricants. You shouldn't expect any better performance or MPG. What's your point?

Everybody wants to go to heaven,.........but nobody wants to die! Better performance & mpg's don't just happen. It requires effort & some expenditures. These Mods pay for themselves & more, but they are required.

Your only getting 15 mpg? Sorry to hear that. You can do a lot better! If you shop around, you can do the Ignition system upgrade for $150. That aught to get you about 4 miles/gal by itself. 4x19gal/tank=76 miles extra/tank or $12. savings/tank. 12 tanks pays for the parts plus you can now lay 6ft of rubber from a dead stop on dry pavement.

blade z51

OK, I went out to look around and saw that the air filter appears to be brand new (as several hoses, etc.). The wires are Motorcraft and they look OK. Likewise the distributor cap, coil, etc. I pulled a couple of spark plugs (5&6), they are also Motorcraft and they look OK and they were both gaped about .046". They might be pretty old based on the rust accumulated on the body though... I might do good to replace the plugs. It's possible that might improve the fuel economy. What is the correct gap for the 5.0 engine plugs?

ymeski56

By looking at that one, I doubt it.
.044-.046 w/ stock coil. after ignition upgrade .056