Ok to clarify the whole plug wasn't ejected it was just the center probe the part that heats up. However the threaded part that remained I was able to remove easily as it was finger tight . Since I've owned it the valve covers have never been off. It is number 4 cylinder Ford numbers cylinders 1 to 4 passenger side 5 to 8 drivers side. As to warranty it was voided years ago, that's the risk you take by modifying them.