power loss: spark? 2ndary injectors? Ideas?
 

The background:
I was driving and all was fine.Shut it off for an indoor errand. At restart, the idle was rough, bouncing between 200-800rpm I didn't think it was going to stay alive.
It did and after running a bit it settled down, but with very reduced power. Car runs and idles ok, but missing lots of power.It has 100,000 miles. I know its a lot, but there are others with much more.

My questions:
What different ways are there to check for spark?

I figure its either spark or fuel.Could it be that the secondary injectors aren't working?

I'm all ears for any ideas.