1997 F150 CD Player Stuck!
Had it do it once before, turns out disc 1 was in upside down.
Also mine seems to be real scratch sensitive, if there's a scratch on track 1 it'll act like the whole disc just isn't there. Try starting the disc on track 2, that trick hasn't failed me yet.
FYI: My truck came with a factory 6-disc cd changer mounted on the driver's side extended cab panel.