I'm not sure if it would work, but try putting the DynoMat sound sheets, under the carpet of your firewall/floormat area. I know they Make DynoMat sheets for your trunk for Subwoofers to avoid trunk rattling, and i'm not exactly sure but they may make one to avoid engine noise too, they sell them at Summit Racing (
www.summitracing.com) or you could try JC Whitney (
www.jcwhitney.com) and i think there pretty cheap, good luck!
