I have this rattle that has been there for awhile. It happens at low rpms in 1st or idle sometimes. If I slightly push down on the bottom of the diffuser on either side it completely goes away. I read a couple thing where people said there heat shield was touching. I bent the heat shield away from the exhaust on both ends (larini dual) but that didnt solve it. It just appears that pushing down on the diffuser solves the problem. So do I need to get this loosened or tightened?