when it trips out, does the 'd' go out on the dash?
if you put a jumper wire in the service check connector ( see here... http://www.nsxprime.com/wiki/Trouble_Codes ) and see what flashes up, the 'D' flashes on the dash to give the auto gearbox fault codes.
Also it might just be worth unplugging the autobox computer and plugging it back in a couple of times, just to cycle/clean the connector.
aka Jonathan!!
'92 charlotte green auto.... as a daily
'37 Ford Y street rod......... something for the weekend!
...... if a photobucket pic is foggy, click it, and it'll take you to the clear version, yes, it's a clicking faff....