Found the pressure/vac sensor easily in engine compartment, but was difficult to find in the wiring diagram and EPC.

Replaced the vac line to the pressure sensor for good measure; also pulled the EGR tube from the EGR valve to confirm EGR valve is not leaking exhaust.

Now I am consistently getting code 23 only after a 2 mile drive. I'll take a longer drive in the morning and will expect to get code 5 as well.

as ever
Paul