Torque Converter?

[Jackpine]

Altitude DOES have an effect, and it actually should improve your gas mileage. The air is less dense so the PCM is going to meter in less fuel to keep the A/F ratio correct. Of course this also give you less power, but once you reach cruise speed, you don't really need much power.

A big consideration, and one that is probably effecting you is the altitude change. Going uphill takes a lot of energy, more than driving on flatland, and you don't get it all back when you come back downhill. That would imply 100% efficiency. So, climbing and descending hurt you more than just cruising on level ground.

Winding roads will keep you in lower gears too, which also hurts mileage. Mountain roads tend to be "twisty".

- Jack

[ticopowell]

Wow, I didnt think altitude would help mileage at all, and yeah hills suck... but the roads arent too twisty, but the speed limit is 45, and on base i dont dare go faster. What I still dont understand is why after cruising back and forth to denver(again 1000ish feet lower than colorado springs) I still get 13mpgs... I would think it would jump to at least 14-15 range, but it was about 13.1 every time i checked... and with the odometer I dont know how accurate it is, but the speedo is about 3 mph fast at 75, so 4%, so should I add 4% to my mileage to get an accurate reading to test mpg's?

[JWBFX4]

Originally Posted by ticopowell

Wow, I didnt think altitude would help mileage at all, and yeah hills suck... but the roads arent too twisty, but the speed limit is 45, and on base i dont dare go faster. What I still dont understand is why after cruising back and forth to denver(again 1000ish feet lower than colorado springs) I still get 13mpgs... I would think it would jump to at least 14-15 range, but it was about 13.1 every time i checked... and with the odometer I dont know how accurate it is, but the speedo is about 3 mph fast at 75, so 4%, so should I add 4% to my mileage to get an accurate reading to test mpg's?

The speedo comes from the factory, about 2 mph fast on these trucks. So I would say its probably correct.

[Jackpine]

Originally Posted by JWBFX4

The speedo comes from the factory, about 2 mph fast on these trucks. So I would say its probably correct.

Right, your speedo is probably reading only about 1% higher than it should be reading, so your miles driven is about 1% off too (it's a linear relationship). Unfortunately, if the speedo is faster than actual, the odometer reading is higher than actual too, so, you're showing 101 miles for every 100 miles driven. This is hardly an earthshaking error, but it means your actual mileage is 1% less.

You go downhill TO Denver, overall, but I recall there's a pretty good climb around Monument I think? In Denver, and at the AF Academy, you're doing city driving. I don't see your mileage as being horribly bad, just not great.

However, some trucks are going to get better mileage than others, due to tire size, tread pattern, inflation pressure, gearing, overall weight and production "differences". You really can't expect to set economy records with a full sized pickup truck. And, I'm suspicious of ANY "high" mileage claims I read about for f150s.

- Jack

[ticopowell]

Yeah that makes sense... The only thing that makes me think is that I was getting about 14 before i got the gryphon put in, now its dropped... and I thought i was supposed to go up... oh well though, cant do much about it til i get my custom tunes in...
Thanks for all the help too!

[Longshot270]

It is really hard to compare people's mpg claims on these forums because most of the time your talking to someone miles away that drive different trucks, different terrain and many other different factors. The two biggest factors I have seen for my truck's mpg are fuel quality and terrain. I can get 20-22 mpg going down one road that has been heavily used and is pretty much smooth as ice until the surface changes to a rougher texture. Then I may go down to 17-19 mpg. Hills and turns also have a similar effect on mileage. These factors compound with engine load/rpm to lower your mileage.

[BlackSTX]

Yeah, Jack said it! Don't be obsessed with the readout, check mileage off of the odometer at fill-ups. Keep in mind that you'll have some variation in filling up the tank, it never stops at exactly the same volume every time.

I can average about 13 mpg all week, and then take a short 30 mile run (with a lot of hard acceleration and cruising above 65 mph) and see mileage readout jump to over 17 mpg. Then if I check off of the odometer at fill up, I can see mileage drop to as little as 11 mpg.
From that I'd conclude that readout is a good indicator of driving style or type (city/highway).

[ticopowell]

From what I have seen so far I get about 13 mpg's no matter what kind of driving I do, I do assume I idle a little more than most people, so I know that can have an effect, but the average mpg's according to the gryphon fluctuate so much that i just use it as a guesstimate of how im doing, and usually it is 2-3 mpg's higher than what I am getting. Again its been only 2 months since I have had the truck so ill see what happens over summer before I do anything about it.

[88Racing]

Originally Posted by ticopowell

From what I have seen so far I get about 13 mpg's no matter what kind of driving I do, I do assume I idle a little more than most people, so I know that can have an effect, but the average mpg's according to the gryphon fluctuate so much that i just use it as a guesstimate of how im doing, and usually it is 2-3 mpg's higher than what I am getting. Again its been only 2 months since I have had the truck so ill see what happens over summer before I do anything about it.

The canned tow tune runs a little richer.
Bill has tweeked it this way for some good reasons.
So that may or might be part of your loss in mpg's.

[ticopowell]

Yeah that would make sense, I am gonna get the custom tunes done over summer i hope... but for $60 each its kinda out of my budget for now, plus I havent done almost anything performance wise except the gryphon, a gott's mod, and just put on a cat back gibson exhaust. then I needed new tires so I got some 35's on there now. It looks great, but i gotta save some $$
I think I will change it over to the performance tune to see if that helps, but with the big tires the extra low end torque might come in handy