Kevod,
When you did your range test and got the plane to act up I assume the engine was running? Is this correct? how long have you been flying with this setup? I would start with that ign module. Also put in a new plug!!!!!! Heat can affect the porcelin around the plug and arch causing random problems. Also possible when you move the wire it pulls on the spark plug? Look for any linkages that could be worn and causing chatter esp. metal to metal... Brenden