yeah the head is 7/16. no there is no way the plug wires are crossed up. i have swapped coil packs swapped plug wires checked the fire order everything i can think of. it just happened to quit after plug change i guess. i have had the truck since 97 so if the bolt extraction and icm reinstall fails i think its bye bye ranger.which hurts me cause i love the truck..just cant keep dumping money in a 17 year old truck..although its never cost me anything till this deal. thanks guys!