Hey I'm 16 and I just bought my first truck. 97 f250 xlt. With a 7.5l 460 engine and just hit the 50k Mark on the odometer. I commute 40 miles day minimum for work and I get horrible gas millage, not average horrible for a 7.5 like 8mpg. I'm getting about 4_5mpg. I've tried everything. New cap and rotor, new air filter(old one was trashed), and lowered the idle. The air filter definitely gave me more power but didn't really help my mpg. I really need help with this because if I don't up my mileage I'm either gonna sell the truck or find a new job ( I like the truck more than the job )

 

Welcome to FTE peterb1213. I moved your thread to the correct forum.

 

The biggest way to increase your milage in the 460 is to SLOW DOWN! I love mine but I drive it like a 85 yr old geriatric. I shift a 2k rpm and accelerate from 0-60 in 9 miles I get 14 highway and about 10 in town. I was going to create a thread about exhaust and getting my 460 to sound real throaty and mean until I got a little road rage and stomped on the right pedal low and behold my big a$$ motor sounds awesome! Around 3k rpm but that eats through a tank of gas in no time.

I remember being 16yrs old, I know how I'd drive my truck if I was 16 again, my answer to you would be to find a Craigslist 4 banger cheap (by cheap I mean almost embarrassing to drive cheap) and keep the '97 clean and awesome!

Sounds like a sweet rig would love to see it !!!

 

Of coarse I've put the pedal down a few times but realized I can see my gas gauge go down even quicker. I accelerate fairly slow and always use cruise once I get up to speed.

 

O and thanks it is pretty nice I'll throw up some pictures later

 

How did you "lowered the idle"?

How old are the plugs and wires?

Have you checked for codes? You may not have a Check Engine Light, but there can still be stored codes and issues that would trigger a code in the Key On Engine Off tests.

 

What is the full story here.

Does the truck have a lift and big tires?
What axle gearing does it have?
Is your commute mostly highway or stop and go traffic?
Are there any codes present?
Does it get the same milage on both tanks?

 

Idle screw,
Plugs I have no idea but wires are as old as the truck I believe
I hooked it up to a code reader and read clean two different times

 

Not lifted (thought about it until I saw tv's mps)
Not sure about the gearing
All highway
No codes
And have only been using one tank I use the other as a backup

 

Check the axle code on the drivers door pillar and post it up.
Does the truck have a 4sp OD trans or a 3sp?

You should alternate back and forth between tanks to keep them from gumming up. There is a common fuel transfer problem with these trucks too where gas is pumped into the other tank as you drive and if that tank is full it gets pushed up the filler tube and dumped on the ground. To check for this run a tank down close to empty and take note of the fuel level, then switch to the other tank and drive on it for maybe half a tank and then switch back to see if the level in the first tank has changed. It shouldn't of course, and you need to check this for both tanks because it can happen to both tanks. The fix is to replace the FDM in the tank that is receiving fuel.

 

It is a 4speed and Ill check the code

I'll try that but I think I would have noticed if it was dumping fuel out

 

Put the screw back where you found it. It's only function is to keep the throttle butterflies from closing too far. They should stop just before fully closing.

Never under estimate the contributing factor of aged ignition components. Get those wires and plugs replaced.

If someone else has jacked with that idle stop screw that tells me there is another root cause of the problem. Probably a vacuum leak which can also cause poor fuel mileage.

 

Next pay day I'll do that, I was thinking about replacing the vacuum wires anyway, pretty old.

 

excellent plan

 

It only dumps out when the tank becomes full. My truck has the same problem, blown check valve in the rear FDM. When I'm running on the front tank the fuel level drops quick, and if I didn't know any better I'd think she was getting worse mileage than my old 460 truck. In reality I know that most of the fuel just ended up in the rear tank which I don't let fill up completely, so it never ends up on the ground.