What is the name of this movie/documentary?

Question

Okay, so I basically can only remember one scene, but I remembered I loved the movie/documentary.

Please help.

Basically the plot of the movie is that the woman wants to kill herself and her children.

The scene I remember is at a gas station (and maybe she thinks she is being followed) and she gets ice cream for her children. And there is something wrong with her car that she did on purpose (and I think someone at the gas station notices or something)

Any help would be much appreciated.

Answer 1

This sounds familiar, but not from a movie.  The exact scenerio was on a Law and Order episode.  The women keeps trying to kill herself and her children, I think she succeeds with a car bomb, but had tried tampering with a heater first.  Any chance that's what your remembering?

Answer 2

Did it star Farrah Fawcett-Majors? If so it could have been 'Small Sacrifices':

http://www.imdb.com/title/tt0098352/

Answer 3

Is there a movie about the Susan Smith story, kind of sounds like that.