That is exactly what it sounds like. I have thumped on them with my fist, just how hard do ? need to thump them? (I know that is like asking how many bees in a behive.) But should I not be able to get them to vibrate at a certain engine speed sitting still?

I am headed out to my shop to get a deadblow mallet and try this again right now. IF this is the case, isnt a defective cat a warrenty item till 100k?

Thanks