Two weeks ago, I lost 50% power in 2008 TL (92k miles) and got codes P0300 to P0304 related to pistons. Right by a Honda dealer, so limped in. They determined that the #2 piston seized and the #4 spark plug lost the ground (missing!). They determined that there was pre detonation occuring which caused the spark plug to back out and allow gas into the threaded area causing built up heat and melted the coil in #2. I had extended warranty, but claim was denied because it was determined (by warranty company) that the spark plug (a non-covered item) was the cause. They need to send out the head to be machined, etc, and the total cost is in excess of $6000. Anyone see or hear of anything like this?