04-08 and some very early 09's had the shit plug design. After that they went back to a one piece plug. Also if you have the shit plug design and want to keep the truck for a long time Champion makes an upgrade plug that is one piece but at almost 20 bucks a plug most people stay away. I have changed so many plugs on these engines that it takes me maybe 20 minutes longer to do. I actually prefer the plug to break in the head and then just use the removal tool. Its pretty easy and straight forward. Also you can spend like 600 bucks and buy the phaser lock outs and tuner and not have the issue anymore either. Friend of mine had her truck start having the issue at 70k. We put the lock outs in and never had another issue with it. She sold it with well over 150k.