Movie with suicide by gas pump

I am not sure why this is stuck in my head today. But, many years ago a movie was on in the background of a garage I was working in. It seemed like a good movie. But, I couldn’t really focus on it. I never could figure out what this movie’s title was. CAN YOU HELP?

What I remember of it: I believe it was set in mid-west USA.
A woman kept her, mummified child in the house with her.
Someone committed suicide by ingesting fuel from a gas station pump and then igniting it.
And I believe the movie ended with a boy, clad in an American flag cape, riding a bike down a dirt road. Then getting abducted by a bunch of teenagers in a car.

This movie may have been set in the 40’s or 50’s

Thanks in advance