Hey,
I bought a 91 f150 a couple months ago and after replacing the wheel bearings, ball joints, rotors, calipers, rear wheel cylinders, and a bunch of other things i decided to take my bed off to fix some rust on it and wire wheel and por 15 the frame.

Now here's the weird part... there is a gas line running from the tank that goes along the drivers side frame rail then becomes turned into a hard line and follows the cross-member right behind the cab. When I took the bed off I realized that the line was broken right where it turns into a hard line. I started the truck no problem and there was no gas spilling out...

What is this line for? Why is there no gas in it?

Thanks. Pictures coming soon

 

Do you have two gas tanks? It could be for the other tank you're not using and is either empty or will begin shooting gas out when you switch it over (if the switch and pump work)...

 

Nope, one tank. Thanks though. There are three lines coming out of the tank, 2 go along the drivers side frame rail and the other (broken) like crosses under the cab as a hard line.

 

The broken line probably goes to the charcoal canister for emission control purposes.

 

Thats it! Thanks! The line going to the canister purge solenoid from the carbon filter has a bolt plugging it.

Does disabling this part of emissions hurt my mpg or anything? Can I just take out the carbon filter and the line along my passenger side frame rail and put a little breather on the end of the line?

 

No the charcoal can does not affect mileage or any of the other emissions, it purges the vapor from the tank upon start up to keep the total amount of unburned hydrocarbons from the atmosphere. Removal of it will not prevent or cause any more evaporation of gas than would occur during the same conditions, the only difference is how the vapors are disposed of.