Still hi-jackin' this thread...it's still alive! THANKS much to XtremeDmax for the help!
Anyway, my problem DID turn out to be fuel injectors. After my dealer refused to fix it denying that there was an injector problem because they had already been replaced around 60,000 miles under factory service bulletin, and since my 100,000 mile aftermarket warranty had expired 2,000 miles ago, in frustration, I posted on this thread. Thanks for the input.
So, my friend is a CHP mechanic who has a shop on the side and he used to be a Chevy dealer mechanic and worked on Duramaxes. He put it on his diagnostic computer and it showed a faulty mass airflow sensor (MAFS) and 2 injectors faulty, and 2 others were marginal (2 on each side). So, I had him replace the MAFS ($150) and replace all eight injectors (Bosch)since he was going to have both covers off. They were $260 each plus $135 core each. But the supplier waived the core for him.
He put it back together and it still smoked a bit, but got better after about 100 miles. Not satisfied, and since he couldn't clear the check engine light, he discovered that the vacuum pump was bad and giving a faulty MAFS reading. So he took the MAFS back and exchanged it with a refund for the difference for the cheaper vacuum pump. New Mobile 1 and filter and Viola! No smoke and runs like a banshee! After labor it was about $3,000. In the end, it really sucks that I had to spend $3,000 to fix a problem GM should have taken care of. But, what choice did I have. Thank God for friends!:rockin
Last edited by sixweeds; 02-27-2011 at 08:14 PM.
Reason: wanted to add a thank you.