Rough running at start up when warm

[JConnerly]

My 81 FI runs smooth when cold but after it has been completely warmed up and you shut it off, if you try to start it again right away it will idle very ruff and threaten to stall. Once you get it going it smooths out again and runs fine at higher RPMs. I thinking maybe a vacuum leak?

[rlux4]

A vacuum leak would cause problems all the time, not just on warm start up. It may be that the cold start valve is activating when it shouldn't which would result in too rich a mixture for a warm engine. Next time it does this unplug it and see if that's the problem.
Ron