I have a 2004 Ford Focus (automatic transmission) with 106,000 miles that makes a rattling sound when I am going under 10 mph. It is really bad when I am stopped at lights and when I back out of parking spaces. If I’m stopped at a light and it is making the rattle, I put the car into park and the noise stops. As soon as I put it back into drive (and have the brake applied) the noise starts back up again. Any thoughts or ideas??
Check for a loose exhaust heat shield.
And check the automatic belt tensioner for the serpentine belt.
Yeah, that’s what we were thinking too.