Big time greenhorn here in both my 91 runner 3.0 A/T and this forum. had random starting problems, i would hear the starter turning but not engaging. usually just playing with the connections on the starter would get it to fire up. I was told it was a bad starter or solenoid but I've since replaced the starter and the problem has only gotten worse. Ive come across the Neutral safety switch several times as a possible culprit but i am curious as to how to test. Any ideas much appreciated.

 

If the starter turns, it's not the neutral safety switch (that just interrupts the power to the starter).

If the drive plate (fly wheel) has teeth that are chewed up, the pinion gear may not be able to slip in to drive it. I would consider removing the converter cover http://personal.utulsa.edu/~nathan-b...39removala.pdf so that you could take a look (you'll be looking at the "wrong" side of the drive plate, but you may be able to use your fingers to feel for damage).

Some on this forum have reported problems where the starter did not sit tightly against the block. With the starter cocked, it won't engage reliably. You could remove the starter, very carefully clean its seat, and put it back in with an eye to making sure it is seated all the way in.

 

If it was a parts store rebuilt starter, I have seen those bad out of the box. I might would pull the starter and run test to make sure the gear is getting extended when engaged.