87 Deville
 

Im wondering if anyone can help me out? I have replaced the Alternator and the Battery and the car still dies while driving and wont start back up again until i recharge the battery.

Electrical!!
 

Electrical issues can be a real bear to figure out sometimes. Start by taking apart all of the grounding points that you can find. Clean up the connection and then apply a bit of dielectric grease and tighten back up again. A good percentage of issues on the older cars is ground related.Check all you cables and wires as you go and see if you find any place where they have worn through and are rubbing on something.Good luck....

Good suggestions from Cadsforfun. I have to wonder whether you have something drawing down the power when the car is not in use.

A common power drain is a faulty trunk light switch. In 1987 these switches were still mercury switches similar to a old thermostat. As the trunk closed the level of mercury shifted and opened the circuit. If it is faultly and the liquid does not open the circuit the light would be staying on all the time. Open the trunk and slowly lower it and keep an eye on the light, it should go out with a few inches before fully closing.

Other sources for power drains, aftermarket alarm, aftermarket radio, power antena with faulty relay.