My 427 87 GT has been dead for a while. I have been working with the folks at FAST to solve the fuel injection problems. In the last 10 months I didn't get to far with them. I decided it had to be in their harness. The computer checked out and the programmer checked out. I checked all the fuses in their harness first. When I got to the 25 amp main fuse it checked out OK for a moment and then went dead. Hmm just like the car. Ran normal and then would just die randomly. I shook the fuse with the test leads still on and it flickered the meter. I took the harness apart and found a nice little groove in the edge of the stainless fire wall. It matched the nick in the main 10 ga. power line. The firewall edge rubbed through the harness just hitting the main power line and blew the fuse. I had slit a piece of rubber hose to keep the firewall from digging into the harness! It must have fallen off at some point. The power line moved around enough that it wasn't a dead short very often. The fuse was laying on it's side. The big hunk burned off inside the fuse would make contact from time to time and the car would run normally. The light on the computer said it was getting power at all times. I didn't, nor did the folks at FAST realize the programmer was back feeding the computer and showing it had power. I have been ranting and raving when it turned out to be totally my fault. Humble pie anyone!