if they did the installation then thats where id be taking it to, and have them look for the problem

 

same thing happend to me except i didnt have an external amp running my mids. The connections from the back of the deck were loose and they werent properly serured with electrical tape and they were touched each other and the back of the deck too. all i got was static whenever i went over a bump and i would have to hit my deck a few times in order for it to work properly. take it back to where u got it installed and tell them to go over the connections in your deck.

 

thanks guys...u have been very helpful!