I am having issues with my 04 6.0 turbo diesel. After sitting for several hours when started and in drive it runs rough like its not hitting properly and blows white smoke with blueish tint.I have replaced the fuel filters, drained water separator and and checked fuel check valves. Also when it runs rough when driving and you put it in neutral is goes bk to running smoothly. Any suggestions where to go from there?

 

yep.......... go buy a Duramax!!