were the other offending cars FI or carbed?
[/b]
EFI.

As I said before, I don't believe it was related to exhaust fumes from the car I was in because of the spotty nature of the effects. I spent one practice session on Sat. with no problems. I was in the car for about 6 laps on Sun. with no problems. The symptoms arose shortly after I caught some mid-packers (I started from the rear of the field), and eased up once I backed off and let them go. Very isolated.

Looking at the results from mylaps I kinda have it narrowed down to 2-3 possible offenders. Maybe with a bit more research I'll have an even better idea who to watch out for.