why does my firebird stall at red lights?

[Joey D]

i drive an automatic 1987 Pontiac firebird and when i am stopped at a red lite the car stalls out it also does it when im in reverse also the oil pressure gage moves around. the idle is fine and i also just changed the alternator.

 

[melsg5]

when is the last time you changed fuel filter, air filter, spark plugs, wires, etc?