Hi, Any new information on (cold lifter) or knocking noise. I have a
02 LTZ, 60K, with same problem. I change oil and filter @ 3K
and used 5W/30W semi synthetic oil, only to get more noise cold.
By cold I'm referring to 60 overnight and 90's daytime. I don't think it's predetonation in the morning only to go away when hot, usually
if your going to get predetonation it's under heavy acceleration hot.
Mine also sounds like a valve lifter, not piston slap. If you or anyone
have new information would be appreciated.