Rough Idle on warm start 1984 500sec

[chitown]

Been having a rough idle problem and have not been able to diagnose what is wrong.

On a cold start the engine turns over quickly and idles very smoothly.
When the car has been off and sitting for 30 minutes or longer and still warm it is very difficult to crank and it runs very roughly when it finally catches.
Sometimes if I shut off the engine and then restart after 5 minutes it will turn over quickly and idle smoothly.

My local mechanic thought it was cylinder #2 that was not firing. He replaced the fuel injector with no change. I replaced the spark plug on that cylnder with no change. The mechanic determined the faulty cylinder by removing the spark plug wires on each cylinder - if the engine ran rougher then that was not the problem - Cylinder #2 seemed to not make the idle worse when the spark plug wire was removed.
Looks like spark is being delivered to the plug since you can see the plug arc as you bring the spark plug wire to it.

I have tried to eliminate the fuel pump as the problem by jumping the contact so that the fuel system remains pressurized - that didn't seem to prove anything.

Often when the engine is idling roughly I can smell fuel that leads me to believe that a fuel charge is being delivered to the engine but not being burned. I was going to try a new plug wire to eliminate that as the problem.

The idle speed is good, idles faster when warming up and then decreases when at temp.

Any ideas?

Thanks in advance.

Mike