95 Astro burning up electrical wire

I have a 95 astro that has always been a dog but my wife loves it and it has 78K on it and it's payed off. But about a year ago it wouldn't start. It turned over and had ignition but wasn't getting fuel. The horn and power mirrors also stopped working. After troublshooting discovered a burnt hot wire terminal in the firewall behind the battery. I replaced the "4-wire" plug and the van started and everything worked. The van still ran rough and it wasn't long before it began to die at stop lights. I had already replaced plugs, plug wires, rotor, cap, fuel filters, ect... it helped some but still seemed as though it couldn't get out of its own way during accelleration. I was at a loss so I took it to a dealer for a diognostic. They suggested replacing some of the very items listed above. I changed more parts but no luck, the van still ran rough and would stop running. I took it back for another diognostic and they suggested the Catylatic converter was clogged. $300 later, the same thing. I took the van back to the dealer and told them to fix it. They replaced a distributor. It ran a little better, but still quit on my wife. Took it back and they replaced a fuel pump. The van did run better, but something still wasn't right. While on a trip, it began to cough and shutter on the interstate. Pulled off and to a GM dealer. The discovered/replaced some clogged emissions valve. The van ran as good as it had in months. But now nearly a year later that same wire behind the battery has melted again? Could the fuel pump be drawing to much power? It does whine pretty loud at times (tank empty or full). Could I possibly have bad ground somewhere? As of right now this is what the van is doing: still kind of guttless / doesn't start as quickly as it used to / 15 mph in the city-18 on the hwy / I know I have short in my dash, but I've pulled the fuse to keep it from draining the battery / hot wire firewall terminal melted / fuel pump whining. This thing is kicking my back side! I would love some feed back!

Seems to be the day for '95 problems.
The problem with the 4 wire connector sounds exactly like weimervan's post.
for the fuel pump problem, try a search with the keyword "pulsator". There is a very long, and agonzing thread that has similar symptoms. After replacing many parts, the problem was the $14 pulsator.
-the caps are not mine, this is cut n paste from autozone's website -INSTALLING A FUEL PUMP PULSATOR WITH THE FUEL PUMP
WILL ELIMINATE FUEL PRESSURE LOSS AND NOISE CAUSED BY VIBRATION.
Hope this helps, good luck.