S4 I337 ATT NB1 Sim and Network Issues.

I’m fairly familiar with S4s even knowing that I’m on a Locked Bootloader. I’ve used work arounds Safe Strap Ect. to Flash Roms, Modules, Modems, and Odin Kernels. I’ve reverted back to stock s4 flagship NB1 Repartition PIT Files. And so on. But since my last encounter with Flashing the 5.0.1. Lollipop Firmware OC3. Problems began. 1st with the Battery. Then the Infamous "SIM CARD ERROR, MUST RESTART DEVICE." And later now only when I’m home I have worst to no Service. Once I leave my Home. Few Miles. Service comes back Stronger than ever. Tower Issue around my home. Have spoken with my Carrier "Cricket". The walked me around a few things. APN Settings. And so forth. But to no avail it’s not really helped much. Oh ya did swap out new Sim card also. Which started the network issue. So I thought. Or could still be. So I’m stuck on the fence. With maybe a corrupt EFS Folder, Bad Hardware or Loose Connections. Or buying another SIM. If anyone has any ideas on this matter, PLZ Help me to Figure this Out.