FYI, when trouble shooting, do one thing/one adjustment/one change then try to start her up. If she won't do one more chance/ adjustment and then try to start again. And on and on and on. The point is if your truck is dead and you fiddle around with fifteen different things, you won't know what exactly did it unless it is obvious. This is the procedure I learned when I was a boat mechanic and is a straight forward way to identify a problem.
As for the idle problem the OP is having, I would also check the in tank pump. Not just the pump but the line in the tank that goes from the pump up. If that line is split (inside the tank) you may not get full fuel flow and an induction of air, esp. when the tank level is below the split. I had the same problem with a boat that had a solid metal tube that went from the top of the tank down to pick up at the bottom. The metal tube broke off at the top of the tank inside of it. The boat would only run when the tank was full but when it got below the tubes supposed location the engine would sputter and die. This problem took a while to find, (not very common, who would have thought).
Anyway good luck, I'm interested to see what you have going on.