so i have a 2005 gmc 2500 duramax and im getting p0299, p0401 and p0404 codes. the truck will go a week straight with no codes and then it'll come back for a day or two. when the codes on its making less boost and when its not there it runs perfect. Im assuming its being caused by build up in the EGR. truck has full exhaust, intake and tune with 150,000 miles. right now im thinking to just do an EGR delete and this should fix the problem... im new to diesels though so some input from you guys would be very helpful.