WORRISOME ENGINE SOUND is a term used to describe the sound of an engine that is not functioning properly. The crossword solutions for this term are RATTLE (6 letters), PING (4 letters), and SPUTTER (7 letters). RATTLE is a sound that is usually caused by loose parts in an engine, while PING is a metallic sound that can be caused by a variety of issues, such as incorrect fuel-air mixture or a faulty spark plug. SPUTTER is a sound that is caused by a misfiring engine, which can be due to a variety of issues, such as a clogged fuel filter or a worn out spark plug.