alexamparo

guys i was having a problem with my 1995 gs. when i would drive it at night and i would be idling with the music on sometimes the battery light would flicker. i took it to midas and they said it was the alternator so i replaced the alternator yesterday adn the car is still doing it. it was a brand new alternator...can it be the alternator wires??what else would cause a car to lose power while it's on? and oh yeah yesterday their was this one instance when i couldn't let the car go under 900rpm or it would shut off. i had to drive it and then put it in neutral until i found some parking. when i got to the parking spot by mistake i let it go under 900rpm and it didn;t shut off. so i stood there for a while with the music on and the car idling,turn it off and then back on and alls well??can it be a loose contact or wire??PLEase HELP HELP