Help-Problems With Power After Warm Up
 

I've got a 87 13b that loses power after warm up. It sounds as if two plugs stop firing and begins to backfire or misfire including a delayed backfire after the ignition is turned off.

I've got extra forecast igniters/ignition control modules and coils. I've changed out the trailing coil with a brand new one, switched both control modules, bought new plugs and wires.

I'm stumped as to what to check next.

Is there anyone out there with ideas? I would really appreciate the help. I'm a total novice with rotary engines so any suggestion would help. Thanks! Don