[km2002]

Thank you for asking, 65comet. I was so frustrated by this, and I got such a short window to get on line and ask for help, that I left out those details.
3.0L engine. Cat converter, resonator, connecting pipe, muffler, tailpipe: All new as of last night. As I mentioned, I think I'm going to replace the O2 sensors just because; and strangely, the replacement converter has a hole on the top side for a third sensor, which my wagon does not use; so I need to get a plug for that (available locally). The odo shows >190K; if that's accurate after almost 20 years, I'd be surprised. Check engine light showed intermittently this morning; it's not flashing at me as if to say the engine will self-destruct in five seconds (my Jimmy was doing that). Started right away, but not real easily; didn't respond well when cold to trying to rev the engine. And while driving, had multiple incidents of feeling like the engine was on the verge of stalling, although it never did.