Exhaust Squeal

[Johnny Danger]

As of late, I've been dealing with an exhaust squeal on the Dangermobile that's starting to drive me f'in nuts ! Basically, the squealing occurs during start-up/idle, and remains prominent until the vehicle warms up. During warm-up, the squealing is most noticeable during short blips of the throttle and/or with falling RPM's. The squealing never fully goes away even when things are up to temperature. But, it is somewhat mitigated when the vehicle is fully warmed up. Strangely, I can isolate and stop the squealing by simply putting pressure on the exhaust tips or pushing against the right side cat delete pipe. Leading up to this, I've tightened every nut, bolt and clamp, to include the muffler strapping to no avail. Today, I went so far as to try and cold set the position of the muffler by inserting a sturdy wooden dowel into one of the exhaust tips and moving the muffler slightly up ward. And, for a brief period it seemed as though the problem had been solved. However, after a few miles of driving the dreaded squeal was back. Any thoughts ?

p.s. The possibility of a defective cat, resonator, delete pipe or clamp as being the culprit, has pretty much been ruled out at this point. It's like an f'in ghost in the machine ?