Originally Posted by
roccobike
I know it's a long shot, but when the broken chain was replaced, did they install an 8-speed chain? The only other thought that comes to mind is lube the cable at all entrances to housing with chain lube. I know it's a long shot, but maybe your cable is binding at the high stress point which is the low gear.
Other thought that comes to mind is that someone threw a new chain on it right out of the box without fitting it.
-R