My wife says that her car stalls at random times when she is driving it.
It happens when she is accelerating or when when she is slowing down, but more often when slowing down. So I don’t think it is a dirty filter or mass transfer sensor, which I would imagine choke on the lack of air flow only when accelerating, not when slowing down. But that’s only a guess.
The engine is a V6-182ci 3.0L engine (Vulcan?).
It would be helpful to say something about the vehicle’s maintenance history. Also, does the Check Engine Light come on when it has a problem (or is it on now). If so, have the codes read (places like Autozone will do this for free) and post them here. Have you asked anyone to look at it and did they do any specific kinds of tests?
If it doesn’t get regular service, then the basics are the place to start - air filter, fuel filter, spark plugs & wires - stuff like that.