ok, I HAD THE EXACT SAME PROBLEM!
mine first started when the fuel pump started screaming, so I got that changed..
Then, it wouldn't start, so I got a new TFI..
but then sometimes it would just stall.. that problem was the distributor point, sometimes the coil would put out a spark, sometimes not.. SO, I'd check the TFI and/or the point.
Good luck !!