Feels Like a Stuck Choke

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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Check the gasket between the throttle body and intake manifold. I'll bet it's sucked in.
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