87 Sierra ignition module problem

Truck runs well until hot then will stall at idle and will not restart until cooled. Trouble code came up ignition module, so I replaced it with a new one. Won't start. Put the old one back in and it fired right up. Everything fuel wise is working as it should. Just wondering on what to check next. 87 sierra 1500, 5.7 automatic 4x4. Thanks.

Ok, when it won't start, you have confirmed no spark?t

Confirmed zero spark with brand new ignition module. Put old one back in it fires right up.