My engine developed a shake/misfire in the middle of a drive

So today i took my car out for a drive and it seemed to run fine for the first 10 miles. Then i slowed down from the 55mph area to a 25mph zone and the car began idling rough, shaking very badly(think everything rattling/chattering), and the car had no power.

I got to my friends place, checked to see if a spark plug wire came loose. Everything seemed fine and I babied the car home. I started it in my driveway 10 minutes ago and it shakes and sounds like its running on 6 cylinders.

Timing is 14 initial, 32 total
Running a self-tuning efi.

Any ideas?