I am an old man that has let progress get way ahead of me.
How old are you anyway? Too old to learn? You must be young at heart if driving two 2002 GT Mustangs! I'm knocking on 60's door myself. So I suspect we are more similar than different. I grew up driving cars with carbs and points.
One of the differences in my case is a Ford reference library to study and learn from. If interested in getting a copy for yourself I maybe able to help. PM (that's private message) if interested.
A small investment in reference materials might save you 1,000's allowing you to keep the cars that you have and not spend $$ on an old car just because of being behind the learning curve. The new cars really are better in terms of safety/reliability if one is honest.
I have no idea what a CKP sensor is.
CKP = Crank shaft position sensor. This is the sensor that tells the PCM where in the rotation the crankshaft is. This lets the PCM know when to spark and to inject fuel. Think of it like a distributor/points/PIP (depending upon how far back you want to go).
Could the code (listed above) be a weak coil?
IF the COP coil was weak, it would be weak all of the time not just in the first 1000 revolutions. In my experience this DTC code is usually associated with a motor base timing problem.
Hence one of the reasons I was asking about the crank sensor and crank damper. Note, sometimes cheap under drive pulleys can cause an unstable CKP sensor signal.
I just read it and got a different code from before (lean condition in bank #2). < that is the before code. Now it says misfire.
Always post the full DTC codes. There are 1,000's of them and they each have a story to tell.
But as an reminder. For a lean related DTC the odds favor a vacuum or exhaust leak.