FiTech EFI system

hey guys, I'm not a old school mopar guy but I'm running the same unit on my blow thru 68 mustang with the battery in the trunk. I have tried everything fitech has suggested and i'm still not coming up with a solid fix. The ecu unit keeps cutting out while driving down the road. I've noticed its better with a fully charged battery, but the unit shouldn't be running off my battery. The alternator is putting 13.8v while running. I've grounded the efi unit to the battery. I've added a ground strap for the front of the engine block, welded a stud to the frame at the rear to ground the battery. I checked my key switched source, It has 12 or move volts.

Are any of you guys running a battery in the trunk? I also seem to get the white screen a lot on start up. I have to unplug the hand held and it will work fine again.
I have also tried a different battery, I have a yellow top right now. Any suggestions would be great I only have 144 miles on it and I've reset it and reuploaded the software 14 miles ago. When the unit shuts off all the gauges on the screen go blank but the back light still stays lite up.