Question regarding the nature of the timing light

I've outlined my diagnostic list for determining the problem with #2 cylinder and the oil soaked plug.

1st: Check the plug for spark. One of the reasons for this is I remembered when doing the valve seals I was trying to feel for pressure on the first cylinder (#2) and couldn't so I decided to pour a little oil in there to see if I got pressure. It didn't change but the point is I thought this was the reason for the oil stained plug so last night I changed to a new plug thinking I'll burn all that oil out of the cylinder by today. I drove it today about an hour and a half and checked the plug when I got home thinking it would be clean. It was not. It was just as oil stained as the previous one. So the next step is to determine if I'm getting spark to that cylinder. Maybe there's no spark there and it's just pushing that oil around (oil from the bad valve seal plus the stuff that I added). So tonight I hooked up a timing light to that cylinder and see it's getting intermittent spark. It has some spark then nothing for a couple of seconds then some spark, etc. I thought it might be the plug wire so I traded it out for another known good one (#1). No difference. I thought #2 pole on the cap might be bad so I change out a new cap and rotor (it was time anyway) and that didn't help.

So the question is, when the timing light lights up is it a indication that an electronic signal is sent to the plug or that the plug is firing.

What can I understand about a timing light which sometimes lights on one cylinder and works fine on the rest. Is it possible an injector is clogged from the oil before I was able to get the seals on?

The next steps are (as time and equipment become available)

Compression check on all cylinders. Pull valve cover and recheck valve seals on #2. Leak Down test on #2 and the rest.

I will say that all the other cylinders are burning beautifully. I havn't seen it look so good since I owned the jeep.

Thanks in advance,

Bill