Hello,
My 2021 Tahoe SRT 5.3L started making this knocking or clanking sound in the engine (video below), mostly does it on cold starts for 1 minute, then it somewhat goes away, you can sometimes hear a random clank while driving, car almost stutters a little when it does. At some points I can feel the car shaking a bit as if it has a mild cam.

Took it to dealership but they couldn't replicate it, said to look for patterns or ways to replicate it. Does anyone know what this might be or had similar problem?

https://youtube.com/shorts/8C0Zzshzz60?feature=share

 

There is a big issue with failing lifters in '21 5.3 motors. Do a search on this site and you will see the reports. GM will not do anything until they fail.

 

tupues: Welcome to the forum.