I had thought about the possibility of bad gas. after sitting for a few minutes, it would start again. Now, it will start, run rough for about 20-45 seconds and die. there is an odd exhaust smell... possibly non-combusted fuel. I will get some seafoam tomorrow and try it. It looks to me like it has to either be fuel or computer related.
I have not modified anything, other than some striping and decklid panel... nothing that makes the car do anything but look different.
Also, intermittently, the service advancetrac message and lights would come on, about once a month for the past 4-5 months. Other than that, the car has run excellent.