1994 1500 5.7l

I still have gremlins in my belt drive.I posted before I was getting some strange knocking/rattling,well that has gone away with a belt change.Now,can anyone tell me why my belt is riding close to the outside edge of my idler and chirping/squeaking like a s.o.b.?I was watching it this morning and all of a sudden it "popped"to the center where it should be and the noise went away,but it only happened that once and hasn't done it since.The belt is fairly new.

remove the belt and check all pulleys; for play (wiggle them) and spin them to see how smooth they turn. Check pulley alignment also.

Thanks for the reply.I have done all that,I even took the belt off and cleaned all pulleys of buildup and still no change.