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Every time I go over an incredibly bumpy street there is this strange vibrating noise that follows. I've been trying to figure it out and I can't seem to. At first I thought it was my license plate moving around, but I've secured that, then I thought it was my muffler moving around and that doesn't seem to be the case. I also thought it might be some rubbing between the tires and car but everything looks fine there. any ideas? I can't seem to figure it out

 
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it could be anything. Can you please explain more (i.e. rumbing sounds like? or front or rear of car?, what kind of mods do you have? etc...)

 
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I've got no mods at all, It does make a rumbling sound actually

 
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Front or back, Driver side or passenger side?

 
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From what I'm hearing sounds like Front passenger side

 
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how many miles? are you still under warranty?

 
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37K miles but it's an American civic in Canada that was bought with a salvage title I don't think the warranty applies anymore lol.

Anyways, I think I found the culprit of the strange noise. It seems as if I'm missing a screw for an inner panel. This is on the bottom of where the door hinges are. On the driver's side it looks to be a black plastic screw. Does anybody know where to get this part. Also somebody please take a picture of their lower front passenger door near the hinge...