Basically it’s about this boy who loves gas station pumps. He is incredibly sad and lonely and often wishes that he could be a gas pump. He eventually starts to turn into one. Also, at some point he eats an abacus. At the end his parents show up and fill their car up at the pump. They don’t recognize him but they say things like “My, what a fine pump!” “Our boy sure would have loved it!” He is happy when he hears this and gives them free gas.

I think I read it at my grandma’s house as a child so that would mean it’s pre-2000s. the story may have been a metaphor for something, if it was my child brain did not understand it. Also possible it was in a collection of short stories, my grandma always had loads of those around.