Diesel Bombers - Starting Issue

Hey guys, after looking through forums on here and trying to get my truck running, I'm still missing something. I got a 2001 ram 2500 that sat up for a year and was running good other than missing 2nd gear, but went to go work out of state and didn't want to risk killing transmission so I unfortunately left it. Came back after the job ended and put 2 new batteries in it, bleed the lines out, and was running fine for the first day. After sitting all day, went to go to store in it and wouldn't crank and fuel pump wasn't kicking in. After turning the key on and off a few times, with bumping the starter in between to see if I could hear it run, and finally kicked in and cranked. After idling for a few seconds it died and been having the same problem. Sometimes it will start with no issues, other times not at all, and I've tried in different temps. I've cleaned the grounds, connectors for fuel pump and the VP44, and even tested the voltage for the VP44(showed everything was good). Fuel pump will run with no problem if I hot wire it straight to battery through a fuse (just in case). Everything is stock and has the in tank fuel pump (I know it's not as good as FASS or AirDog, but haven't had money to get yet). I was wondering what can I check next, or if anyone had this issue and what the fix was. Thank in advance for the help, and if there is anything I left out, let me know and I'll update with any new info.