OnTheHoist.com

A user named "gotnospark" over on the cartalk.com forums posted his difficult-to-find fix for his 94 Altima whose engine would cut out after approximately 30mins of driving (bad cam position sensor). He questions the pre-testing of the remanufactured distributors sold to him by Nissan and suggests putting in an aftermarket unit.

To quote:

"The moral of the story is that '94 Nissan Altima distributors seem to be notorious for cam position sensor failures. I believe the remanufactured units are not envoronmentally tested at engine operating temperatures before they are declared "fit for service". That leads to bad units being sold and reinstalled.
The new distributor that I installed came from Distributor King, a Canadian company that gives a 3 YEAR warranty on their unit. and the price is less than $200 with overnight shipping. I highly recommend them if you need a distributor replacement.
I hope this help someone else out there struggling with a recurring "engine quits" problem, and that it saves some of the frustration of being stuck on the road. "

The full post can be found here.