I hardly ever drive my truck. 03 F-250 5.4L W/ 60,000 miles. The last few times i have driven it maybe thirty miles each way back and forth to home depot while building my deck over the past month, it seems to be sucking down gas faster then usual(maybe this is in my head because of the gas odor???). While driving if i come to a stop with the window down i can smell a strong gas odor, this is when i first noticed it. Then After i park the truck and get out i notice a relatively strong gas odor. its hard to pinpoint but i crawled under the truck and noticed a strong odor around the gas tank but dont see any leaks. i also notice the smell under the hood near the firewall on the drivers side. Other then the smell and possibly worse than usual gas mileage( need to test this thought though) the truck seems fine and runs great. no MIL light or any other cause for concern. Any thoughts or personal encounters with this issue will be greatly appreciated.

 

I would recommend to find someone with a smoke machine or take it to a shop with a smoke machine.

 

oops, double post

 

It's funny my 03 had a similar problem when I first bought it. I could smell gas fumes toward the front of the truck. Raised the hood, couldn't see anything amiss, closed the hood, ignored it. After a couple of days it started to really concern me so I looked again Raised the hood, looked for the charcoal canister, located it on the driver side inner fender. Then I noticed the main line that carries vapors from the gas tank was unplugged, plugged it in, no more gas smell, done deal.

If I were you, I would start at the canister and work towards the tank.

 

Well you could trace the canister lines, But if you have that many miles, and it sits a lot of the time and your getting poor gad milage, I would be willing to bet you have a leaking injector or two. or if any part of your fuel lines are rubber, they are either cracked or hard so that they only leak when it has the pressure of the pump behind it. and then evaperates. A canister vapor line isn't gonna play with MPG.
When vehicles sit for long periods of time without being ran, seals, o-rings, and rubber lines start to harden and leak... thats why they say that if your vehicle sits for more than a week, just go start it and let it run for a few mins. Just so things get lubed and stay plyable.

Just a thought, but it is still a very good practice!

 

check your fuel filter. i had a similar problem and when i finally looked close the filter on mine had rotted out and would leak under acceleration. no puddles while it sat and it would leak on the inside of the frame rail and wasnt noticable from the outside. it even passed state inspection form a dealer like this. scary.also the filter wasnt even 6 months old ,purolater POS

 

Thanks Guys lots of helpful info i will Def take a look at these things

 

Thanks. Fuel filter was the problem. took a good look and noticed a stain on the frame rail. as you stated Joeycyph56 it would only leak under a load my wife hopped in the truck and gave it some gas and then you could see a steady drip until she let off.

 

As i stated before it would not leak at idle only under a load (a steady drip). i looked in the manual and its says system Fuel press is between 30-55PSI. does anyone know if this is variable press, dependent on load, or should the fuel Press stay a constant press? to me it seems its variable due to the nature of the leak but i always thought that fuel press was a constant. Just curious on the topic, trying to stay educated.

 

I went through this also. My evap cannister line was dried and cracked. I replaced it and it eventually went away.