I would love to see 11 miles a gallon right now. Im getting like 8.

 

Good suggestions!

 

Well first off stop using up the whole tank. When it gets to a quarter tank or so, fill it up. You are going to be real mad when the truck won't even get the fuel out of the tank.

As far as usage, whats your gearing, do you tow, and how many days does it take between fill ups? Have you tried using a different gas station? There is 1 gas station by me where I get noticeably worse mileage.

 

im in a similar boat 04 lariat crew cab with 68k with 35x12.5 and a leveling kit.. im at 10.1-10.2 according to the computer im doing a real test with the trip now..

when i get rid of the cai im ganna try cleaning the tb and maf and ill try and squeeze a fuel filter in to wile im at it.

 

You have 35s, so thats a pretty big difference. If you don't have 4.10 gears, you are probably getting terrible mileage, and gearing is your issue. Also you have wide tires, so there is a lot of resistance.

 

I have 3.73 gears and 33x11.5 tires. I get the same mileage from any gas station. I found a thread where a guy replaced his 02 sensors and it helped. Im gonna do that and the fuel filter and see if it helps. If not I will try the injectors. Thinking about this, My mileage has gotten cosiderably worse ever since I first hooked up my gryphon and the CAI. I got the bad cat a few months after the gryphon and CAI. I returned the truck back to stock (intake and tune) when I replaced the cats and the spark plugs. Is there a possibilty that the gryphon jacked up my fuel/air ratio?

 

I have an 05 screw 4x4 3.73 as well and mileage is 14-20 mpg.

So yeah something is amiss. calipers sticking or something?

 

Ok, I get it...your milege sucks before AND after the mods. You may have a drag somewhere...possible sticking caliper could cause this. After a drive, put your hand on each of the rims. If one is HOT, it could mean you have a sticking caliper. You may also have a drag with your parking brake so check that as well. I doubt if the injectors will affect your mileage in this way. If I am wrong, I'd am curious to know why.

 

I can't really wrap my head around what you are saying. What difference does it make how low the tank gets before refuels? I routinely fill up with 25 gallons and my gas mileage is the same as if I fill up with 15 gallons. As long as you aren't constantly driving the truck till there's only a gallon left in the tank you're fine. The fuel pump needs to be immersed to keep cool, but there's no reason to fill up at 1/4 tank if you don't want to. Drive till the low fuel light comes on.

 

It's documented that consistently running it below 1/4 tank can lead to shortened fuel pump life.

 

Where is it documented at? Apparently I'm an outlier in that document since I have run every car I have owned down to the low fuel light and never had a hint of fuel pump failure. My last F150 (98) had 140K when I sold it and it never had an issue.

 

Thats bogus...I asked a Ford technician that, and he said only if you run it dry will it damage the fuel pump.

 

I had a mechanic tell me to run my tires 10PSI higher than what it says on the sidewall. Does that sound right? Mechanic said so, maybe I should do 20PSI over what it says just to be safe

 

Yeah try it.