First post here. I hope its not a stupid question.

I have a 2001 Lightning with about 67k on it. All thats been doing is routine maintenance, doors locks, and spark plugs. I've been noticing a very faint squealing noise when I start up in the morning or after the truck has been sitting for a while.

I'm assuming this has to be the belts loose or old? Does anyone have experience with this?

 

Welcome!
Sounds like a belt. When you start it up and hear the noise, give the belt a quick spray of wd40. If the noise goes away temporarily, it's the belt.