Hi Eric, my Monte did the same thing when I bought it, I rebuilt the carb but it still did it. Turned out to be carbon build-up in the intake manifold. The center of the intake manifold has openings to a plenum which heats up and releases the choke, (at least on my '71 it is like that) and it would do exactly what yours does on cold mornings, in the afternoon if it was warmer it would not do it. So off with the intake and got it tanked and cleaned and painted since it was off and Monte runs perfectly now. Just my .02 worth.