Fuel/ electrical problems

The multitude of symptoms suggest there is a broken ground wire in the rear of the car. The fuel pump may be finding a ground through the brake lights and tail lights. The way I would approach this is to pick just one circuit and concentrate on that. Start with the brake lights and observe if they are full, normal brightness. Use a stick between the seat and brake pedal to hold the brake lights on, then measure the voltages on all of the wires on one of the brake light bulbs. You should find twelve volts on just one of them, and zero volts on both of the other wires. If you do not find two wires with zero volts, remove the bulb, then see which terminal in the socket has twelve volts. That is the one to ignore. Look at the other wires to see which is the ground wire. Follow that to where it bolts to the body. It will have a break somewhere. If you cannot figure out which is the ground wire, I will dig up a wiring diagram to help with that. If this car uses the newer 3057 bulbs with the flat plastic base, those sockets usually have labels molded into them near where the wires go in.

You are welcome. Keep me posted on your progress. I will be back tomorrow to see how you are doing.