Idles at 1200-1500 RPM cold or hot, runs rough,
feels exactly like a stuck automatic choke.
But there is no choke - it's fuel injected:

   1992 Buick Roadmaster 350 TBI.

The (ODB-I) connector showed no malfunction codes.
I removed the IAC valve (it looked like new) polished
the pintle and seat and reinstalled it with no change
in performance.   I will remove the EGR valve tomorrow.
Is there something else I should start looking at?

Rodan.
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