i have an 07 V6 with ford racing dual exhaust. since installing it at certain rpms i hear a rattling sound from under the car. it usually happens when i pu tit in reverse, when it hit between 2 and 3thousand rpms. im wondering if it could be a hanger or something. i also have a squeaking sound coming from the engine. it occurs right at startup and throughout the rpms range. im thinking one of my belts could be loose. any thoughts??