-Losing voltage as car is running? HELP?

you can bypass the wire from the bulkhead connector by running a heavy gauge wire from the battery terminal on the alternetor directly to the positive on the battery. this will completely bypass the amp gauge. I had to do this on my car because my charging system was doing the exact same thing. Found out later it was the post on the ammeter gauge itself in the dash cluster, broken connector at the gauge. So I just left the bypass wire in place until I replaced the gauge and the car charged fine. Hope this helps.