ok guys i start my truck its on high idle sounds great runs good. then when the high idle turns off it makes a knocking sound and smokes like a b!@#$. I was thinking it could be the fly wheel (stupid dual mass!)

what do you guys think

 

What color smoke? Sounds like it could be a bad injector.

 

If the smoke is gray would that be a bad injector or possibly a head gasket? Cause mine smokes too and not in a good way.

 

smoke is white

 

could it be your throttle spring could be hangin up on the IP?

 

Sounds like an injector is stuck open. The knock is preignition and the white smoke is unburned fuel.