Batteries are easy to load test. That is a basic thing to do to make sure they are good. They can go bad at any time, so age means absolutely nothing. That said - your truck, your decision. We are just trying to help across a big internet, with only your posted observations to go off of. My advice is probably worth exactly what you are paying for it ....... That said, I wish I had a dollar for everyone that said it wasn't their batteries when it was .... happens more often than you would expect.

 

Well what I can do is take batteries out in morning and take them to autozone have them load test them. I believe you in saying they could be bad but would that really cause my truck to shut down? Well suppose it could if charging system takes a plummel and then voltages drop. Just stinks want to get this resolved and time is crucial right now when I daily this truck. Or should be and not my Jeep which is my wheeler lol. Speaking of supposed to be using truck to take jeep to Oregon two weeks so I'm hoping we can resolve it.

 

When you are cranking, it is nearly a load test. You don't want your battery voltage to drop below 10.5 volts when cranking. Even better is if it doesn't drop much below 11. Your FICM is sensitive to low voltage - even if it has been rebuilt. It can shut you down if you have stressed it due to whatever reason - weak batteries, weak relay, etc.

You mentioned a Leece Neville alternator. Was the old one bad? If so, did you have the new batteries installed w/ an old alternator that went bad? These are the things that can affect new batteries.