Misdiagnosis and a heart attack

Anybody ever noticed this? With the car at idle, if you listen at the air intake on the passenger side rear quarter panel, it sounds just like a water pump going bad. You know, the sound a water pump or bearing grinding away just before it lets go. In this case it's the sound of the air being sucked into the engine at the intake. While doing a walk around last night with the car at idle, standing at the passenger side door, I would have sworn my water pump was going because of that classic sound. Put your ear to that air intake and listen. It will frighten you to death. Once I figured out where the sound was coming from, I put my heart back in my chest. lol Any other "misdiagnosis" anyone wants to make claim?