Don't know if it will help, but the inhibitor relay on my 86 1/2 hardbody is on the passenger side near the battery. I put a photo up in my member gallery if you'd like to take a look. Not sure if your model has one.
It can be bypassed by shorting out two of the connectors on the underside....I made a spade to spade wire. It's been awhile, but I believe the two connectors on the 'front' side of the relay....in the image, the connectors with the red plastic on the plug....are the ones to use for bypassing the relay. Sorry I don't have the time to check this out for you myself.....so be careful!
When you go to a Nissan dealer, they'll be the first to tell you that they sell a lot of these. I think you can get them for half the dealer price at rockauto.com . At RockAuto mine looks something like this:
http://www.rockauto.com/ref/ACDelco/...html?E1788.jpg
Let us know what you find out......I've come across several people who still haven't completely solved this sort of intermittent problem.