Fuel Pump Issue?

Go over to MyMopar.com and download a free factory service manual

There's a procedure in there for checking the pump. You need a cheap pressure/ vacuum gauge from the parts store.

Possibilities in no particular order:

Tank pickup sock is gummed up, or the pickup tube otherwise plugging AKA runs awhile and then sucks something in, gob of dirt in the sock, whatever

Flex fuel hoses PARTICULARLY the two on the suction side, are collapsing or deteriorated internally. "New" does NOT mean "terrific", "better than anything," or even "works as supposed to."

I see you are from WA so I'm guessing the wx is not terribly hot, but "it might be" that if you somehow mis-routed the line, it might be picking up exhaust heat and boiling/ vapor locking. Don't discount the weird--like an exhaust leak at a muffler/ connection, etc, blowing hot air directly onto the tubing.

This is likely not a vent problem, but they are simple. Look in the trunk. The tube running down beside the fuel filler tube simply open ends in the frame under the trunk. There are various things, mud daubers, etc, but you say you've opened the cap.