This engine was making a loud ticking noise like injector noise but more. I was told by the dealer (henniger toyota) that I had a collapsed piston. I decided to tear it apart and have a look for myself. The piston skirts were not collapsed, the cylinders still had hone marks with a very slight ridge and the bottom end connecting rod bearings were still good. There is a lot of carbon gunk above the last ring and there was a lot of carbon on the top of the cylinder. I figure my engine noise is the carbon on the piston sliding tight on the carbon at the top of the cylider barrel.