Thanks for the thoughts, but I'm having a hard time understanding your hypothesis. Is it really possible for that much carbon to exist between valve and seat? I have never seen buildup like that in any engine I've had apart over the years. The impact of closing always knocks the seat area clean. No...

jamfu, Thanks for the thoughts. My lifter noise sounds identical to what I occasionally hear on a cold start after the car has sat a few days. This leads me to beleive it's excessive clearance, due to one of the lifters not pumping up properly. An overly tight valve would burn in no time, due to no...

My impression is the seafoam did exactly what it was supposed to do. Clean your valves and injector. However, you have to think about what is really happening when you clean the excess carbon off the valves/seats. Material will wear down over time . Especially at the valve seat. Allowing for the val...