1989 Ranger 2.3L idles funny then dies?

[delfs]

I have a 1989 Ranger with a 2.3 manual, and when you start it up it seems to run fine for about five minutes then idles really rough and dies.. you can drive it but it wants to die..but it runs fine at about 3000 rpms but if you down shift it backfires. It dies every time you stop and i have no idea whats wrong with it.