Any smog experts out there?

If the o2 can be read Live data..you'll know if it's bad.
But if it's cycling 0.1 - 0.9 it's normal and working fine.
maybe it's an exhaust leak 'would have to be a pretty substantial one though'.. or stuck open pcv maybe... typically something that is below the throttle plate and before the O2 sensor.

Because all it did was sit for years things like chewed vacuum lines and bad gas come to mind...
@cudamark
Wait a sec..the transducer could be bad, you vac tested the diaphragm of the egr but not the transducer?
See if its stuck or frozen.
Pull vac through it, is it switched off when the key is off?