Engine goes rich and wants to die.
When I was working the bugs out of my Demon and there were bugs, I had the same problem. I had a Holley Blue fuel pump and regulator. From time to time the Hemi would bog down, black smoke would come out the exhaust and a couple times it stalled. The problem was, the regulator mechanism in the pump would stick. The pressure was more than the external regulator could cope with and the carbs would flood. I replaced the pump and the problem went away.
Bruce