1990 Beretta Indy Wont Run with alternator

My beretta has been giving me trouble for a while now. The car runs fine when it is running off of just the battery. it can run until the battery dies. When I pop the red wire onto the alternator the car will run until the battery is fully charged and then the car revs up dies, revs up then dies. it does this until it stalls after a few minutes. its a new alternator and i had it tested. i have never experienced a problem like this and have no idea where to go next :crying:

If the alternator is ok, may need an "Idle Learn" procedure..