I'm looking for what is called a "backpressure variable transducer"
(BVT for short), the analog equivalent to the DPFE sensor.  The BVT is
black, round and has two diaphragms inside, with three port fittings
coming out.  The E port goes to the exhaust header, the B port goes to
the EGR air tube, and the C port tweaks the EGR vacuum signal based on
the backpressure differential between the exhaust and EGR air tube.

What happens is after so many miles the exhaust gasses wear out the
rubber diaphragms inside.  I popped the covers off and confirmed this.
So rather than try to rig the diaphragms somehow with RTV I thought I'd
try looking for a good one somewhere.  A junked car would likely yield
the same results if I could even find a donor vehicle.

An old parts list might help, but haven't found any yet.  Anybody old
pros around familiar with fixing or replacing these?.  I called a
dealership and their parts diagram didn't list the OE number anymore
because it was obsolete, I was told.

Thanks,
sleepdog