At Hallett the car would hesitate and stumble getting out of corners.
It seemed like a mid RPM issue, going away above 4000.
Fuel pressure was steady around 40 while stumbling, on a full tank.
It was always heat related, happening after a few laps.

So far I've replaced: plugs, wires, cap, rotor, ignition control module, and coil. All looked or tested fine.
Replaced fuel filter at track.. no change. I could change the fuel pump, but with steady pressure, its probably not the issue.

Bring on the GM jokes along with some advice.