I have a 2006 lbz. I run a ppe excellerator on 160 tune. I drive my truck like an old man. Every now and then I have to smoke a rice burner. I have noticed a slight vibration in nuetral and park only. It will vibrate for about 3 seconds then stop and then 3 more seconds and stop and keeps on repeating. It will not vibrate in gear. The dealer says it is normal. I do not believe that. It is not very bad, but it is annoying. My friend has the same truck and his is doing the same thing. Any ideas?

Could be the variable geometry turbo. The computer will change the pitch of the vanes and you can get a slight vibration. Mine makes some cool exhaust notes when it does this. CVhanges from a deep rumble to a high pitched jet engine sound.

I Have not noticed a sound difference when the vibration occurs. I will have to check it out. Thanks for the info.

yea i ve heard those newer turbos do that too it sounds really cool