Gas tank issue

[swice]

Gas tank is developing worsening vacuum in the tank when removing cap for fill up, any advise on how to find and clear the vent?

 

[Steve McMahan]

The vent line might be plugged. You will find it exiting the top of the fuel tank, at the front. It connects to a metal line, which runs up to the engine compartment. Disconnect the rubber hose there. I would then find that other end in the engine compartment, remove the rubber hose there, and using compressed air, blow the metal line out. If that is clear, and both ends has intact rubber hoses, you need to check both of those rubber hoses for restrictions. Let us know what you discover.

 

[swice]

The vent line might be plugged. You will find it exiting the top of the fuel tank, at the front. It connects to a metal line, which runs up to the engine compartment. Disconnect the rubber hose there. I would then find that other end in the engine compartment, remove the rubber hose there, and using compressed air, blow the metal line out. If that is clear, and both ends has intact rubber hoses, you need to check both of those rubber hoses for restrictions. Let us know what you discover.

Thanks Steve! I’ll try that. I ran into a big problem about 10days ago I left out of Fort Smith Arkansas heading for South Dakota. Prior I went over the car carefully and it had full service, and running great. About 200 miles out my FMX trani suddenly would not shift into high gear, the auto shift from 1st to 2d was ok, but would hang second no matter what, I found someone in Tulsa to put it on a rack, mod lines cked ok, linkage ok, so I suspect something bad happened to the internal clutch I guess, I eased it back home in second, swapped cars and I’m due back home this weekend, when I have the trani pulled I’ll have them ck the tank vent, many thanks, gotta keep my stang going!!

 

[rvanamb]

A quick fix would be to buy a vented gas cap. As replacing the rubber hose would mean dropping the gas tank. A vented cap would keep you on the road till winter, when you could drop the tank to fix it.

 

[Vern Cook]

I know it's not polite to hi-jack somebody else's thread but I thought I saw an opening.
This fuel cap came with the car when I bought it and I just wanted to know if this is a venting cap and if it only vents suction pressure or both?