How do I test distributor to see if its bad or needs replaced? 2002 Nissan terra 3.3 non supercharged

A scope can be connected to the signal line to the PCM is the best way to check the Dist output but you can also take resistance readings of the primary, it should show 1.0 ohm at 68 degrees and the secondary resistance should show 10. k ohm at 68 degrees. Keep in mind there are several other thing's that can cause what would seems to be a Dist problem. From the Dist to the PCM, a lack of power (12V) or shorting intermittently to ground, a ground problem anywhere in the system can also cause various problems and of coarse the problem has to exist while your testing it. About where your Dist is, when you open your hood, to the right you will see the air box where the air filter goes. Follow the large rubber hose out of the air box and just where it attaches to the intake manifold the Dist is slightly left and forward. It has 6 plug wires plugged in to the top of it. A warning: If your thinking of replacing yours with a used or new part you has to know how to reset the Dist timing. Once you pull your Dist out you will see it is gear driven off of the camshaft. If it's not replaced properly the ignition system has no way of knowing where top dead center of the pistons are and will cause a permanent no start and backfiring thru the intake manifold and possibility of a fire. Before you start throwing parts at it and causing more problems that will cost even more in repairs I would say take it in to your independent repair shop and have it tested and repaired. I see cars everyday people spend hundred's of dollars in parts and do not have the skill to complete the repair or the parts they replaced were never the problem. Also keep in mind this sounds like a solid state elect problem and it has to exist (act up) during testing to determine just where the problem is located. So It has to be happening at the time it's tested or there is no way of finding the problem, simple ohm's tests can only show a bad part when it's bad. This is what's called a intermittent drive ability problem and very few shop's or tech's have the skill required to troubleshoot intermittent elect problems. Most just throw parts at them in hopes of a fix or get lucky and it act up while in the bay which isn't very often. I speak from 35 years experience specializing in performance, elect and driveability problems. Good luck, Tim