Why won’t my car run after cleaning the engine?

I own a 1993 Honda Accord and it’s ran perfectly since I bought it a year ago. Recently it has been leaking a little oil but I couldn’t really tell where it was leaking because the engine was so dirty My bright idea was to get my son to clean the engine. He did and when I got back in the car it started right up but by the time I got to the end of my road it was acting like it was out of gas and would barely even idle thenn it died and hasn’t started since. Please give me some ideas.