sometime - not always - I hear a very pronounced whine coming from under my 6, seems to be located mid to aft. It is a pulsating sound and occurs both in gear and in neutral and either moving or parked. I'm not too savvy mechanically but when the car is stopped I can't think of anything that should be moving aft of the engine. The only thing maybe is the fuel pump? I haven't been to the dealer yet - thought I would check here for ideas first. Thanks.

 

I have heard sometimes the heat shield has caused rattles on other peoples mazdas...Id look into this a lot more, I have heard it causes a rattling noise!