[spa01s2k]

I'm thinking the octane rating has nothing to due with your problem, the car should be able to adjust itself and not stall with a lower octane gas. However, it does sound like you are having fuel system problems. My dad had a 2003 Ford Lightning that only had 6000 miles when something similar to your situation happened. The truck was not idling correctly and tried to stall several times. Took it to my work scanned the computer, everything seemed ok, but still ran horribly. Filled up the tank the next week and the truck ran considerably better, but still not right. I replaced the fuel filter which was packed with a ton of sediment (unusual for 6000 miles), and it took care of the rest of the problem. Maybe your dealer used some bad gas from a local station?? The filter is in tank on the S2000 and isn't easy to change, maybe just run a few more tanks of 93 and see if the problem goes away.

BTW- sorry for my random story, just tyring to give some insight into your problem.