Ever since I purchased my car there has been a grinding noise as I can best describe it coming from the rear passenger side of my car. This grinding can only be heard when my car has passengers or when I'm alone and I accelerate. When I have passengers the grinding can be heard all the time during the ride, but when I'm alone it only occurs when I accelerate to catch up to traffic but cannot be heard when the car is coasting. Anyone have any idea what this can be? My suspension consists of stock strucks and shock from the look of it and lowering springs.