Ok I have just read up on AutoRx and somewhat educated myself on it. Sounds to me that it is an outstanding product that is very well engineered. I have an 02 Mustang GT(4.6L), and I started using Amsoil in it at about 15K, I used the Amsoil motor flush prior to the Amsoil install. The oil in the engine(MC 5W-20) had about 4oo miles on it, I put a new cheap-o filter on it added the flush and followed the instructions. I was very surprised as to how dirty the 400 mile oil was when I drained it, it was black as night, no visable sludge though. I use the Engine Flush every other OC as I do use extended drain intervals with the Amsoil(which is appx every 30K). Would there be any advantage to running a AutoRx cycle(with conventional oil) as I imagine my engine is fairly clean with what I do?