I replace the battery and starter on my 86 it ran fine for a day and then the battery died, i jumped it and it will start right up and run for about 2 minutes and it dies again and I have no electrical power, I had the alternator tested and they said it was good, I didn't believe them and replaced it anyways, the car did the exact same thing, and now I'm stuck.

Any ideas?

 

Check all your wiring first make sure everything is tight and correct. This includes your battery cables to the battery posts. Loose battery cables will cause an alternator to run all the time and it'll burn right up even in a day. Have you measured the battery voltage with the car off? Then start it and measure while running. If your alternator is charging you should see like 14 volts or so with the car running. If it's externally regulated the regulator might be toast. Measuring voltages with a voltmeter if you have one will be a quick test that might point you in the right direction. Another test and I will throw out a disclaimer here (so use at your own risk) is to start the car and once running pull a cable off the battery. If the car continues to run then your alternator is charging, if it dies there is a problem with the charging circuit or alternator. Don't let it sit an run like this just a quick test for a few seconds and shut the car down before you reconnect the cable. You don't want to zap any computer stuff! Good luck.