Thanks guys, looks like I have some homework to do. I'll have to take it out soon & try some of the proposed troubleshooting.
Getting a little ahead of myself but got all excited when I viewed this video on YouTube where a British outfit found a kit that replaces the entire exhaust for 600 pounds (not quite $1000 U.S.). But damned if I can figure out where they got it.
https://www.youtube.com/watch?v=oS_yKQRcln0 30:33 mark. Probably wouldn't meet U.S. spec anyway but was hopeful I could find something equivalent in U.S.