I installed my 12" alpine type r to almost complete my GN alpine combo. Just need the amp and deck. Well, anyways, i had it turned up, and i realized something by the gas tank was rattling. I got down on my creeper and circled the rearend area and realized that the sound is coming from inside my gas tank. I have no clue on what it could be. It has an aftermarket poston fuel pump in it. The sound is definitely coming from the drivers side about 3" in from the side and towards the front. If anyone could help me out it would be great.