Ok so my pickup don't start with a these days. I've put on a new starter and solenoid and it starter right up after that. but every now and then it won't start just clicks, what could this be? I would like to permanently fix this as my dad wants me to go a newer vehicle and I don't want to, so this doesn't really help the situation!

 

I had a similar problem on my 98 check your power wire and ground on the starter

 

Connections

 

Yea make sure they are good wires and clean

 

does it only happen after it rains? damp? then change your wires going to the spark plugs

 

If you disconnect the ends of each connector cable & check continuity on each cable, you will likely find one w/ "out of the ballpark" high resistance. These are weak links. https://www.f150forum.com/f33/how-big-3-upgrade-46822/
Even doing this upgrade w/ 4 AGW would help.

Also, Stressed Battery's tend to have this problem w/ greater frequency. A Battery is stressed when it is continually roller coastered between flat line & full charge. Also usually causing the fluid to drop. Requiring water to be added so much, the acid charge become diluted. Next stop.....dead cell! If you ever add "any" type of water other than "distilled" it's history. A " special "load test" will tell you what's really going on.

Also w/ the key off. disconnect the negative terminal & measure for voltage between the terminal & NEG post. Should be minuscule. If notable, you have a dead short to ground somewhere. Many times it will be a pooched diode in alternator.