Green car has a miss

It has been running rich lately, (which means it smelled like gas,) and a little bit rough.
I thought it might have a miss, but the reason is a mystery.

I took it to Don today and he is super busy.
All week he has been working on this car, changing it from a 305 to a 350:

The first thing we checked for were any obvious wires loose on my own car, but there wasn't.
 Kevin ran his laptop and it was showing high levels of unburnt fuel running by the oxygen sensor.
This gave them a clue that one injector or cylinder isn't firing.
Apparently the O2 sensor tests one side (which is 4 cylinders) and it might be on that side.

I hope it is just an injector. They are used, but not often known to go bad. Stock injectors go bad all the time.
It could also be the coil (part of the distributor)

I wanted to blog about something, so on Monday I'm going to document what it takes to test the injectors.
Don is super busy and not excited to do this, so I'm going to try to do as much, myself.

I didn't have time to visit the paint shop before work, but a friend of his said he is super busy.
Tax refund time is coming up soon... I wonder how long it will be before I get in?