[36Goat]

I noticed what sounds like an engine knock. It sounds like it is in the plenum area. As you idle up it does not get louder, but can here it as the RPM's come down. Is this normal? My car is stock, just bought it used with 8,000. only put about a 1,000 on it. Any help would be grateful.

 

[Holden]

The only thing I know of is piston slap. Both the 05s Iv had did it and people talk about it on here. Normal for LS2 goes away after warms up. If yours is persistent could be trouble.

 

[36Goat]

It did it while it was hot. Checked the oil, started it back up, noise was gone. Shut the car off for about two hours, started again, bam noise was back.

 

[Holden]

Sounds like might be piston slap they are built loose from factory. I would do a search on here for more info. I was concerned @ first. Just drive a couple mi before you jump on it.

 

[Cottonfarmer]

It did it while it was hot. Checked the oil, started it back up, noise was gone. Shut the car off for about two hours, started again, bam noise was back.

My '05 chatters a bit when cold started but after a mile or two the noise is gone. I think what you are hearing is piston slap and is nothing to be concerned about. My Goat has a bit over 17,000 miles on it now and it has made this noise since new. -Jim