Does your truck have the 3 valve engine? (silver valve covers)I thought the SuperDutys still carried the 2 valve engines (black valve covers). If you have the 3V engine, they have variable valve timing. The cam phaser consists of a hub on each camshaft where the chain attaches, a solenoid which controls oil flow, etc. This repair can be done with the engine in the truck. Requires special tools. If you have the 2 valve engine, you don't have the VVT engine. You may have chain tensioner problems. If you run anything heavier than 5w-20 oil, you may have worn those parts. The oil journals are small and the thinner oil gets to those parts faster. I am still aquiring the tools to do the job myself. I have the service manual. I will post how the outcome is. THe spark plugs have horror stories. I agree with you on leaving them in. I now have near 104,000 miles on mine, they won't seize any more than what they are now. However, if you have the 2 valve engine, you shouldn't have any problems with seizing spark plugs. They had more problems with them ejecting at start up, especially #3. Two relatives of mine have vans with the 2V 5.4 with over 150,000 miles on both with the original plugs and still going fine.