So, I've had my 2006 is350 since july and haven't had any super major issues, but this new noise just started showing up about a week ago. So far it has happened twice, once when the engine was cold, sat in my garage at about 70degrees overnight. Other time it sat for about 1.5hrs after a 5min drive, so it wasn't completely cold. The noise sounds like metal against metal. I called my father, he is my car guru, i'll admit I know nothing about these things, and he just said something about lifters or crank or something, but said it should be fine. But it worries me. He was also like its under warranty don't worry about it.
I dunno though I had a "beater" for 10yrs and never heard such noise ever when starting it, cept once when i broke a spark plug off and part of the ceramic fell in the engine. Anyways it a loud metal on metal noise that lasts maybe 1-3 seconds. It has happened twice out of the last 20 times or so starting my car. But it has never happened before. I only have 8200 miles on the thing. Has anybody else had this issue? Should i take it into the dealer? Should i just wait and bring it up at my 10k service? Oh yeah and I checked the oil, its full.