You have CIS correct?

I vote for an injector that is dribbling rather than making a mist. Black is a rich mixture / miss fire.

The bump you are feeling, is this when you are opening the valve ( pushing on the stem ) or compressing the spring to remove the keepers? If pushing on the stem, this is semi normal on high miles motors were carbon builds up on the stems. When hot it could be holding the valve open but there are few things to try first.

With decent compression your problem isn't likely to be valve related.

Start by swapping the wire , plug and injector to another cylinder to see of problem follows. Have a very close look at the cap for arching at cyl 1. Yes i know this is new but we need to make sure. Did you reuse any of the plug wire ends? There is a resistor in some that can fail and cause your symptoms.

If none of this helps, and you have CIS, move the fuel tube on the fuel distributor to one near by and see if problem follows. The fuel distributor isn't " timed" to engine rotation so moving a tube isn't an issue.