I just got my car back together (it had been parked for a month or two), and I am having a voltage issue that I cant seem to figure out.

PROBLEM:
While I'm driving the voltage is at 14v (according to the volt gauge), but when I let off the throttle, the voltage will drop to 12v and then pick back up to about 13v at idle. Sometimes, the voltage will drop so low that the car would just cut off.

If the car cuts off, it wont start again. The fuel pump doesn't prime when I turn the key, and the car just keeps turning over like it isn't getting any fuel. After about 5-10 minutes it will start back up again.

Yesterday I was driving the car and it cut off again, but this time when i tried to start it, the fuel pump did not prime AND the AVC-R wasn't getting any power. After about 10 minutes everything worked again.

IDEAS:
I tested the alternator and the battery, and it turned out that the alternator was going bad. I replaced the alternator, and the problem is still there.

It seems as though I have all the symptoms of a bad "main relay". Does a bad main relay cause voltage issues too?

Any ideas are appreciated...I'm stumped.

 

UPDATE:
I replaced the main relay, and now the car cranks up every time. The car still has the voltage issue though. What's the next thing to check?

Any ideas would be greatly appreciated.