Timming a 1997 chevy and finding the wire to unplug

These are usually located on the firewall on the passenger side under a cover that looks like the letter T.remove the cover and look for a tan with a black stripe wire,this is the wire that needs to be disconnected with the car running you should hear a difference in the idle.set timing and reconnect wire then check to make sure check engine light is off.if not start motor disconnect wire,turn off motor and reconnect wire start motor and check the light it should be off.