So after taking Winmutt's suggestion to redouble my effort in finding plumbing leaks, I found one on the pressure side, one of the hard plastic lines was slip underneath in the Y connector, and clearly a lot of air was escaping there on closer inspection.
Also found an exhaust leak in the flex coupler on the down pipe, it's right at the base of where the stainless mesh and the pipe join. About a 1 in tear along the perimeter.
Has anyone successfully repaired or replaced the exhaust flex coupler? I'd like to finish all of the repairs before I head out to test for success
TIA