92 S10 Wont run right

I have a 92 S10 Blazer and have been trying to get the timing set right but not sure what it is supposed to be set at. It is a 4.3 VIN W. Also, while trying to adjust timing, idle will flucuate terribly, high idle then drops to almost dying. Hope someone knows....

Are you unplugging ESC Connector prior to adjusting the timing? It is located on the emissions label under hood. But should be -0- degrees (p) or (n).