Hot starting issues

So was able to swap out the distributor today and now it will restart at will so that problem is fixed. However now I’m having idling issues. It was backfiring out the tail pipes/popping but i seemmed to have figured that out. Now its making a weird thump. I tried increasing timing and it went away, but then when I got to adjust the idle speed screw To lower the rpm it comes back. My idle mixture screws seem to be happy as they are in the 12-14 range on the vacuum gauge. What am I missing here?