About 2 weeks now I was leaving a job and truck wouldn't start, would only click when turning over key. Had AAA come jump me and no problem - started right up. Got home and turned off truck only to find the next morning truck wouldn't start again. Grabbed my jump box and vroom started right up no problem. Had the alternator tested and tested fine, even pulled off negative cable while running and stayed running so I went and bought a brand new battery since the previously battery tested and was bad/dead. Well I've also noticed that at times I will have to wiggle a wire or battery slightly and power is regained. So it definitely seems like a bad ground or bad positive wire cause once truck is running then it runs without any issue until the moment I shut it off and then it loses all power until jumped again

 

With it running, hold battery cable's, are they getting hot? If so, you have a loose connection.

 

I just looked under the hood and the one ground wire that goes from chasis to hood is missing. Not sure how important that ground is or isn't

 

That IS the main ground for the battery! fix that first!

 

It's such a short ground strap though and only goes from firewall to hood. I read somewhere that's the ground for like radio interference and what not, no??

 

Did you clean your terminal ends? Or replace them they do wear out

 

Correct. The body panels are grounded together to help with interference. That is not what is grounding your battery. The ground wire from your battery should go to the engine block. I had that same problem. Over time that wire connector breaks and needs to be replaced. It didn't stop my truck from running.

Have you had the starter tested? As they get older some of them short internally and it shows up when you go to start the vehicle. Once started it is not a problem until you need to start it again.