Fuel pressure specs needed

About two weeks ago I filled my truck up with gas an when I went to start it, it started real rough idle wouldn't go over 500 and it bogged out and shut off. Started it again did the same thing so I gave it a little gas and it stayed started. Didn't have another problem until I filled up again and it did the same thing so I thought maybe I was just over filling it cause I always top it off to the nearest half dollar or dollar. So I stopped topping it off thinking maybe it was maybe backing up with fumes or something. Haven't had it do it since until today. It started right up, I drove up the street a couple blocks to the post office shut it off an when I came back out to start it again it did it. I haven't done a fuel pressure check yet but I did get under and listen to the fuel pump and it sounds fine. No whining from it or loss of power while driving or anything. It's just random on a couple start ups. Was wondering if you had any ideas on what it could be?

No that's what's throwing me off. I'm not a certified mechanic but have vocational training on automotive repair. Asked my dad because he has worked on trucks all his life he said could possibly be fuel filter or pressure regulator. I was leaning more towards something to do with vapors as the most common time it did it was after I filled up with gas. I never let my truck run past half a tank either so maybe that's causing a buildup somewhere or a faulty Purge canister.

That's what I figured too. It's only happened about 4 times now 3 out of the 4 was after filling up and after I got it started and drove it for a minute I would shut it off and and start it back up to try an recreate the problem and it doesn't do it.

Do they just open up once you take it off?

Ok I'll give that a try. Thanks!