Vent tube on Gas Tank Sending Unit?
Ok cool. Is it usually 1/4”?
That is for later models w/a vapor management return style system. You could run the three fitting style inline mopar filter if You wanted to run a 1/4" line back to the tank.
Proper placement and vertical orientation for the filter needed tho'. As is, You can just cap it off and forget it. As posted above, Your vent goes up to the top of the filler neck,
and down through the trunk floor boot for the filler pipe. The top end of that vent tube is rounded where it is inserted into the short hose, and closed off to a very small dia.
pinhole. If You are having fuel delivery issues, and loosening the cap helps/eliminates them, there may be an obstruction such as an insect, debris, or spider webbing.