95 3.8 with 250,000 vacuum issue

My 95 has had a loss of power and a cel for a couple of weeks. Soon afterwards the larger vac line running from the DPFE kept popping off from the exhaust line side. I've replaced both the DPFE and the vac line and still the same issue. Any ideas what's causing the high pressure build up?
I had the codes read but lost the paper. I seem to recall "lean bank 2" but that is about it.

Plugged catalytic converter.