that what i was guestamating at..

i checked the tires this morning and they had about 28 psi in them i filled them all to 45psi like posted above so im hopen that helps

 

with my 04 5.4L f150 screw i drove for 6 hours at 75-80mph and got 16mpg with 265/70/17s they are filled to 35psi, i have a 2.5" level kit installed, the gotts mod, and straight exhaust with all cats. it was -25 celsius all day i thought that was pretty good mileage. i think at 55 or 60mph i can do closer to 18mpg. i mostly driving country and town roads ive been getting about 600km on about 100l. so thats 372 miles which works out for around 14mpg city. i have squeezed 434miles in summer. but that was about 30 gallons. not sure if my set up helps? the intake mod and straight exhaust? but i can see 35s losing mileage but not sure i can see that much of a loss? def go for the gotts mod, its easily done!

 

More psi should gain you some mileage, I know mine all leak down slow, seems like when i pump them back up it helps for a while. Winter gas sucks too. I went from about 15-16 mpg to about 12 on stock tires.

 

i bought a stock intake from a guy on here and i plan on doing them mod when i get it..
if i could get 14 mpg id be happy.

thanks for the info

 

well i got 45psi in them now im not sure what im supposed to have in them.

 

Depends on the tire. Load range? I have Discoverer ATR load range D and I use 42/40.

Draw a thick chalk line across the tire and drive a hundred feet. See where it's worn. If you have more chalk left on the middle, add more pressure. More left on the outside, lower the pressure. How long have you had these tires and how did you not know what to fill them to? Keeping your tires properly inflated is probably the easiest thing you can do.

 

I'm not very good at all of this, but if the above is true... wouldn't that be very suspicious that the prior owner may have slapped some 4.56 gears in there and the door jam may no longer be valid... and the prior owner probably just took his edge, or gryphon out, or just returned to stock from an SCT or one of the other programers...

I think you should look up a good gear ratio calculator... have someone pace you, or get a GPS with MPH reading and figure out how far you are off and if the speedo says you are going faster or slower than the GPS states... you should then be able to calculate your approximate gearing based on tire size, RPMs, and actual speed...

 

dude b4 u go all crazy on me i just got the truck on Saturday.. and the tires came with it.. This is my first truck even though i liked them, I never really researched anything... the tires are Kumho Road Venture MT 35x12.50 r 18 L T

and i dont haul anything yet but if i do it wouldnt be anything crazy.

im just getten into trucks if u got any questions about fox body mustangs i could probably tell ya an answer or tell you who could help you.

 

ok so my mpg prob is alot worse than i thought i just went for a little drive and my gps is like 2mph slower than my gauge reads and that could be because i couldnt keep a containt speed due to wheather conditions

im not hard on the gas and im getten 10.5 mpg not in 4x4..

i bought a stock intake from a member here so i hope that helps a bunch... and im not thinken that i should get like 18 i just want something more reasonable like 12-14

 

When you're speedo is off, it's a percentage, so it'll be closer to real at slower speeds and further off at higher speeds... I can't remember where the best gear ration calculator is, but I'l recommend looking one up specific to our ford transmissions that you can can plug RPM and GPS speed into with your tire size in order to get your rear-end gear ration...I'll bet it's close to 4.56...

EDIT: try this, see if it helps:

http://www.4lo.com/calc/gearratio.htm

If you were going to do one thing to it first, I'd recommend a tuner, one that accepts custom tunes... then re-evaluate your mileage issues once you get things sorted... that way you can keep your Intake (or actually put it back on once you get your tunes)

See MGD's sig for the links to those places, as they are the best around...

Welcome to trucks, you'll enjoy turning a wrench on these probably as much as you enjoy it on your mustangs... if not more, because they are bigger!!!

Searches are your friend, look also at the tech articles we have some good ones...

 

i wanna get a GRYPHON.. but money is tight right now so its ganna take a while.. maybe with my tax refund money (if i get any)

i dont plan on keeping the 35inch tires.. i might step down to like 32s or something .. i love they way they look but not the price or the lower mpgs

 

Just be careful... If the rear-end is 4.56, you might not want to do that... though there isn't MUCH difference between them... If you're just running around town/towing or something you'll like it, but if you get on the highway cruising at 70 will take your RPMs above 2000, plug in the combination of tire sizes to that calulator to see...

 

i dont think i have a gear in my truck... i got a gear in my stang and its the same as the truck (stock 3 73) and it doesnt seem like the truck has an asston of lowend like it would if it had the gear

 

i think thats part of the reason for the ****ty mpgs not haven tall gears