[NOBBC] Any thoughts on a starting issue?

[Greg Badano]

Hello all,
 
I am hoping I can get some possible trouble shooting
suggestions for diagnosing a starting issue that has recently developed with
my car.  It starts up almost immediately but it's not firing on all
cylinders.  It will lope along for a few minutes this way and then I can hear
and feel the missing cylinder(s?) start to kick in here and there until it
finally all six are firing the way they should and it idles smoothly at 500
RPM.  Revs and drives just fine after this initial rough period as well.  It
does this consistently if it has been sitting a while.  I pulled all the
plugs, cleaned and re-gapped them thinking perhaps one was fouled.  For what
it is worth they were all pretty dark.  Maybe this is related and maybe not.
 
Any thoughts on what might be going or how I might isolate the problem?
 
Thanks in advance for any thoughts and suggestions.
 
Greg
1959 AC Aceca