Well Norwalk is a very sticky track. My guess would be that your car isn't making enough power to overcome the rolling resistance. The rolling resistance is huge for sticky track.
I highly doubt it would be something with the PCM, if you can load it up to 3500 RPM everywhere except Norwalk. What is some of the info on the torque converter? Does it has a converter clutch (i.e. locks up)? The PCM will dump the lock up if it sees certain situations, like braking. It could also be that the converter clutch is locking up right away and you aren't getting the torque mangnification that a toque converters does with fluid.