Nasty J

I've got an 05 with the 5.4 in it and I've been throwing a 442 emissions leak code occasionally. First time it was because I left the truck running while filling it, then it happen two more times. I replaced the fuel cap, it went a while before throwing the code again, but now I've got two codes that came up, system lean bank 1, and the 442 code again. ****s driving me nuts. I can't see any damaged or loose hoses or connections, and I know it's not the cap doing it. I have thrown the system lean code once before but it came up as bank 1 and 2 so it may have been bad gas or weather...