Isuzu Repair: Rodeo misfiring, unlead, electrical tape

Question
I have a 92 Rodeo. It was running rough so we changed the plugs and wires. Found 1 fouled plug, but when we started it after changing them, it is now misfiring pretty bad...black smoke, barely running. I was told by several ppl that soomething (sludge) probably fell into one of the holes when he was changing the plugs. How in the world does one go about cleaning out those holes? Could there possibly be another problem? we didnt do anything more than change the plugs and wires and did those one at a time so as to not get wires crossed.

Answer
Well I wou;d duble check the wire routing. Also make sure none of the wires are wrapped together with electrical tape as to cause what we mechanics call a "crossfire". Where they actually switch firing orders(very bad). One of the wires could have come loose or they were not installed tightly. The sludge can be cleaned out by adding some very heavy duty carb cleaner and running unlead plus fuel. Although it is very hard to get it 100% clean without removing the head Linda.