My '05 has 78k miles with cyl. #8 misfire. Brought it to my buddy's shop. He changed the coil as a hopeful fix then moved to the plug, couldn't get it out. Soaked it down and of course it broke off. That's when he learned someone else had been there once before! It had the newer plug in that hole! I bought the truck with 8 miles on the odom! So a call to the dealer found that at 5 miles, they put all new plugs in due to multiple misfires on the DTC. Now the problem, he thinks the head will have to come off. Using the correct tool for these plugs, he's pulled about all the meat out of the sleeve and it still hasn't moved. The first ever for him. I'm thinking of having him change all the plugs now. Then if the theres another in the other head, he's almost there for the removal anyway! What do yah do?!! Don't know if I really want to keep it at this point...