Smokey Duramax aka "Durtymax"

My 03 GMC Durtymax 2500 4X4 Extended Cab smokes like a bonfire with wet grass at idle. It cleans up at cruise and gets great mileage otherwise. But let it idle for a few minutes and you may think the
swat team is smoking out a bad guy. Anyone ever heard of this? If so your help is appreciated. I have had it back to dealer twice and they have not offered any suggestion.
Thanks, Matt
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
intake gasket going or possible ring problems

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.