Hi, I just do a master rebuild of the 1FZ-FE. The engine is rebuild with 0.25 clearance not standard. I notice a BIG loud noise when cold start or when the truck is sitting for 3 to 4h. The Knock noise last for about 2 seconds! the times that RPM goes up and down when starting. What is this noise? Sounds like a Rod Noise! but I replaced all the rod bearing during the rebuild. What it can be? Piston Slap? Bad Tensioner? It's killing me now, as I rebuild to get it of that noise and now its still there. What can be bad or cause that? Thank you A.