I had an intermittent stalling problem consistent with those mentioned in the thread. after much trouble pinpointing the problem it turned out to be the engine harness. the problem occurs where the harness bends down toward where it enters the firewall by the passenger side strut tower. while shaking or hitting the harness in that spot I was able to reproduce the problem. it didn't happen every time but often enough to know it was the problem. after trying to pinpoint the 1 of 100 wires that had the break I gave up and just re routed the harness slightly so that there were 2 softer bends in the harness instead of the one 90degree bend. so when it was flexed by engine movement less stress was put onto the harness. I never again had the problem. there is a FSB about it. and here it is.
http://www.lyberty.com/car/Maxima_A3...NTB98-008b.pdf
good luck