Truck Repair: 1983 Chev Truck-Starter is intermittent, neutral safety switch, starter solenoid

Question
Just recently I started having problems with my truck not starting.It would just 'click'when you turned the ignition switch,then after a few times it would fire up.So I cleaned the battery cables,as they were a little dirty,and that seemed to fix it.Alas,a week later it did it again,this time I took the Battery & Starter to NAPA to be checked & both were fine.At that time I bought both battery cables & re-installed all,only to still have this intermittent problem,sometimes it fires right up &  then others it just clicks,but when it does engage it whips it right over. Any help would be appreciated! Thanks  

Answer
Hello Dennis,
You may just have a loose connection, and I would guess it is in the wire that engages the solenoid.
Check all the connections, from the ignition switch, thru the neutral safety switch, to the solenoid on the starter.
A volt meter connected to the starter solenoid terminal during the problem would be ideal, but that is difficult.
And even though they tested it, the solenoid could have an intermittent poor connection inside.
I know those Chevy starters are located in an imposible place to access, but when it does it again, if you could measure the voltage to the small wire at the solenoid and see if full battery voltage is getting there.
I'd bet it is a little low, and if you jump across from the battery cable terminal, to the small wire stud, it will spin it.
There are a lot of connections through the firewall, and at the switches, and any one of them loose will do that.
Another thing to check is the ground wire from the firewall to the engine. Make sure it is clean and tight.
Van