4Runner hard time starting and sounding funny and then...

It was gone. Basically I had a hard time starting my 1999 4Runner, it wouldn't turn over. I turned off the air, and tried again, then since that didn't work I tried again. Well it finally started, but it had this really weird sound, like a dry wheel spinning somewhere, like an old rusty bike wheel. I opened the hood and listened some more but couldn't figure out where it was coming from. And so I thought that I would need to take it to the shop asap. Well literally five minutes into the drive, it disappeared completely, like it was never there. Weird, but I know there is someone out there who has a good idea of what it may be... PLEASE HELP!! I don't want to pay through the nose if I don't have to...