Mid. Temp. stall/start problems. Need help!

I have a 92 s10 blazer with the 4.3 vortex. It does not start at mid temp. about 170-180 degrees. It also stalls sometimes at the same temp. It starts and runs fine when cold or at full temp.
I change the ignition module,starter,plugs, wires, cap and rotor.
I am ready to sell for best offer because of this problem. Any help greatly appreciated!