Bad Plugs/Coils ?

[14Boxter]

If anyone has an Idea on this, I would appreciate the info!

I was out of town for a few (4) months so the car sat. Returned and had to jump it, it
ran fine. 6 Months later, it started to take more revolutions at start-up before the
engine would start. The engine would run a bit rough while idling. I figured that maybe
the aged fuel might be the cause so I added some octane boost/injector cleaner and
immediately the car ran/started as usual. I continued this process for maybe 4 tanks.
Then the other day I filled the tank with just plain 92 octane premium. I drove about 7
miles and suddenly, the car started to bog out and run very rough. Starting from a stop,
I had to ease into first gear to get going. I had to ease into the throttle slowly or I would
(seemingly) flood the engine. Once I reached speed it seemed if I kept even RPMs, it ran smooth. I pulled the plugs but they didn't seem to be fouled. Now I start the engine and
it runs rough with the "Check Engine", light on. All fluids are current and topped off. All I
can figure is a problem with the, "Spark." I have 52,000mi on a 2001 Boxter S. Anybody
have any suggestions?

Thanks in advance for any assistance!