Toyota Repair: 2007 4 runner sport

Question
I am having issues with my 4runner starting.  It started 4 months ago.  You turn the key (no clicks) it does nothing & then will all of a sudden start up & drives just fine. It will do that for about a week; then it will not do it again for a month or so & later the problem will come back.  I have put in a new battery (even though tests showed it was fine) & I have had it to the shop 2 times & they are unable to find the problem because once I get it there it will not do it for them.  Very frustrating! I am told the starter checks out fine; actually I am told nothing comes up on the diagnostic as bad at all because it starts every time they have it.  What could be the issue?  It has 120,000 miles & has had a tune up just a few months ago as well as regular oil changes..  Please help!

Answer
I assume it is an automatic transmission, there may be a problem with the neutral start switch located on the side of the transmission where the shift elector is, first it should be checked to make sure the 10mm mounting bolts are tight and not corroded, this can cause a bad ground condition, if this is not the problem try replacing the NS switch