I have been searching around for opinions on improving mpg and I notice that everyone sorta has a different opinion and are also divided on what works and what doesn't. I bought a 92 F-150 SB STD cab with a 302 and completely stock a few months ago and I have been trying to improve the gas mileage and I think I am on to something. It orginally got about 16 around town and 18 on the highway. Here is what I did.*** Please keep in mind that all of these tests were done on the same 140 mile stretch of road and at about 60 mph.***

1) Changed my driving habits. I quit using the cruise control since the ground was pretty hilly and the cruise would over compensate to keep me at the right speed. I also tried to average 60 mph(in a 55). I felt like this was neither too slow nor too fast and got me where i wanted to go in a reasonable amount of time. By driving as nice as possible, I went from 17-18 ish to a solid 19mpg.

2) Added a fairly large toolbox because I needed more room for my junk. Surprisingly that actually caused for my mpg to go up to 21. I guess it just changed how the air flowed through the bed and caused for less drag.

3) Swapped out the factory intake with a new K&N FIPK2 and saw an increase from 21 to 23 mpg. This was incredible to me. I really never thought I would ever see a V8 truck go up to this kind of mileage. Some notes about the K&N if you are interested... I was alittle disappointed at the packaging of parts by K&N. Some of the smaller assembly parts were missing from the package but it was nothing that I couldn't fix with what I had at my house. I DID NOT disconnect the negative battery terminal like the instructions say to do b/c I am lazy like that and didn't think about the effect on the ECM until well afterwards. I do not know a lot about the OBD1 systems so I don't know if the ECM will eventually "adapt" to the new intake and increase or decrease the mpg. If anyone has any insight into this please chime in. But as of right now i am plenty happy. I did notice a considerable increase in noise from under the hood due to the huge amount of air rushing into the intake. I actually think it is kinda "cool" so it doesn't bother me. I can only hear it at statup, low speeds, and extremely high acceleration (wich BTW it probally the best sound from a truck that I have ever heard in my life... sounds like a bad a** motor with this intake).

I do not have the around town figures yet and I am going to do more averaging as I drive around more. FYI, while playing with the K&N I saw my mpg go to 14.

 

Sounds good, a lot of guys here would kill for that kind of milage. FWIW, the K&N kit you have converts the stock cold air intake to a hot air system that flows more... despite the fact these are widely marketed as "cold air kits". This can produce negative effects if you drive in really hot climates at slow speeds where under hood temperatures can get way up there. In this case this type intake would actually hurt milage and performance because the motor is injesting the super heated air, hot air is less dense and produces less power. The other downside is that more dirt is being inhaled along with all that extra air, but again this may not be a big issue depending where you are and how often you need to change your air filter, somebody that drives on dirt roads mostly will see accelerated engine wear.

The only reason I can think that K&N would recommend you disconnect the battery is to erase the built-up adjustments the computer has made to fuel and spark and revert back to the factory base maps. This would produce a temporary increase in performance from richer mixtures that would make it appear that the intake produces better results than it really should. By doing it the way you did you get a better idea of the real effects the modification has all on it's own, the computer would bring you back to where you are now anyway given enough running time.

What gears does your truck have BTW?

 

"3) Swapped out the factory intake with a new K&N FIPK2 and saw an increase from 21 to 23 mpg"

If were mine I would bolt the hood down with carraige bolts and threaten to "shoot on site" anyone who attempted to raise the hood!

 

No way that truck consistently gets 23 MPG. No way at all.

 

i did not want to be the one that said that is not possible mileage but i do agree with andy.

 

I agree that the numbers seem odd but then again, I have been religious about measuring my gas mileage for several years now ( I used to drive a dodge with a 3.9 V6 and no matter how hard i tried, the gas mileage was always 14 around town and after a fresh oil change went to 17 on the highway if I was lucky). I know I am calculating everything correctly... fill on flat ground put the same amount of gas in after it clicks off, reset odometer before i ever crank the engine... etc. Let me say for the record that I don't find much enjoyment in driving the way that I am driving now to get these numbers. I am slowly speeding up after stopping at a light or sign, letting the hills slow me down and speed me up since i am keeping the pedal at the same position as much as I can. I have had to mentally remind myself throughout the whole trip that I am trying to conserve gas. A lot of it may be due to the time of year and the temperature outside. I also need to mention that these numbers were obtained while i was also not using the AC and left the windows halfway down. That may have something to do with it also. One last thing, this truck was babied by the previous owner. It only has 85,000 on it and on the first day that I got it, it shot smoke out of the tailpipe when i floored it to get up on the interstate as I blew the "cobwebs" out of it.

Again, it isn't "fun" or "carefree" driving, but it does equal up to 23 mpg. I will be averaging the numbers as I drive around more so that I can verify it.

 

Occasionally high mpg can be had on particular fill-ups, but it is the overall average that is more important. The 55 to 60 speed range is about the highest speed that one can go an get consistently high mileage in these trucks. So, to me it is always good to hear high mileage reports once in awhile but they are just that once in awhile reports.

 

I got 20 mpg in my ext cab on a trip tp Dallas on I -35,.... w a hell of a tailwind

 

I would love to even see 16mpg

 

What size tires are you running?

 

i actually believe him, cause i can get 17mpg in my 90 f250 4x4 351w 5-speed, and im runnin 33x12.5 inch tires.

 

I doubt that story just as much. Did you install a new speedometer gear to correct for the larger tires? If you changed the gear ratio as well, did you install a speedometer gear correct for the gear ratio and the tires?

If you base your mileage off of your odometer, then your odometer has to be accurate in order for the mileage numbers to be.

 

Uh-oh, its getting worse guys

 

think what you want on the highway i get 16-17mpg, in the city its about 13mpg. just because im new(er) to thi s site doesnt mean im new to trucks. im with the original poster.

 

Did you change the speedo gear? Have you checked your speedometer with a GPS or mile markers?