May be several things.
-Clogged fuel filter
-Weak fuel pump
-needs a tune up
-bad Idle Air Control Valve
-dirty air filter
Now the car should not die if the air filter is dirty but a combination of what I listed may cause the issue. Have you changed the spark plugs on the car at all? Im going to bet its a bad idle air control valve. Or it could be a loose vacuum line in the engine bay. Does the car idle rough when in neutral or park? Is it hard to start?
We need some more information to get a precise idea as to what may be causing the issue. Oh and welcome to the forum!